-=Z28=-

iTrader: (3)

Msgt Luttrell, Thanks for the reply. Yes, block seems to be in good shape. I know when I built the motor the first go, everything was done to it. line hone, resurface, bore and hone using fixture and deck plate and that wasnt many miles ago, 4000 or so. Otherwise it just sat in storage.

I sure hope it goes together good. Calling dyno guy tomorrow to see what is schedule is like.

Thanks

Dan

skinny z

I'd be interested in seeing that video. In all of my attempts at calculating the proper push rod length, that is with the SBC standard pedestal style rocker arm, I've come to the conclusion that Jim Miller's half lift method is far and away the most reliable and least prone to interpretation (aka. the witness mark method).

http://www.engineprofessional.com/do...2010_20-30.pdf

It's a bit of a read (although I found it all very interesting) but the meat and potatoes is near the end. There's an excellent illustration and the instructions are easy enough to follow. I've attached a few pictures of my setup up. Of course, how you go about is entirely up to you.

As for the cam timing, advanced or retarded, that decision is partially based on what your compression ratio ends up at and how that relates to your cam. If your DCR is dismal because of a lack of SCR, you might be inclined to advance the cam and help regain some of the lost cylinder pressure due to the late intake valve closing. I'm also in that situation as I mentioned earlier. My cam is just a little on the large side when stacked up against my 10.2:1 SCR. I could take another .5 to 1 full point more to really optimize the combination but I'm limited in that regard.




The old wooden caliper is used as a reference plane. I needed something to measure the trunnion and roller tip centrelines from.




The allen key represents a measurable distance from the reference plane to the trunnion centreline. (5/16ths in this case)




The Vernier measures the distance from the reference plane to the roller tip centreline.

Subtracting the former distance from the latter should equal half of my valve lift. I worked the adjustable pushrod until I achieved that value. This is with the lifter on the base circle. No checking springs are required. I used them just to stabilze the testing jig. Once I had pushrod length figured out, I saw that the roller tip was getting very close to the edge of the valve stem. So much so that I opted for Crower's offset trunnion roller rockers. This set the rocker .050" back from the valve and brings the tip more on centre. This sway I get the narrowest sweep across the valve tip and it's in the middle. Couldn't ask for more.

-=Z28=-

iTrader: (3)

Here it is, this guy knows his stuff.

-=Z28=-

iTrader: (3)

Them r some nice rockers.. Is that puppy or kitty hair? Stuff gets everywhere. I have the same issue... lol

skinny z

Crower offset trunnion rockers.
Cat hair.

Orr89RocZ

iTrader: (20)

Thats the beauty of shaft rockers. Properly designed stands, you can do 90 deg mid lift and position roller dead center of the stem

Highly recommend them even tho they cost as much as the heads sometimes haha

skinny z

If and/or when I revisit a high performance Gen 1 build again, I would definitely consider going that route. The open road events have a lot a appeal to me and the shaft rocker system is the kind of insurance I'd be looking for when sustained max RPMs are involved.

-=Z28=-

iTrader: (3)

Today was a good day. Got my parts and went out to machinists shop to drop crank and other stuff for balancing! On the other hand, my electric fan for my van went out on the way home. I barely made it. The bearing went out. Glad I caught it or it would of chewed a hole in my radiator. Going to be late for work.... Hitting up the local junk yards in the a.m.



Springs, locators and seals showed up today. Comp Products was out of the retainers so they are coming from summit. Should be here tomorrow.

skinny z

Do you have flow numbers for your heads?

By the way, I just watched that video for establishing proper geometry. What he's done there is take the mid lift method in that paper I posted earlier and gone about measuring the values in a slightly different way. What you'll find with your beehive spring retainers is that there's no flat surface on the top of the retainer and nothing to lay any kind of bar stock or alan key on as he's done. This is why I made up that little jig that fits under the retainer. Then it's just a matter of measuring from that jig to the appropriate points on the rocker.
The other thing I noticed was that he never ventured into the contact point of the roller tip and where it meets the valve stem. In some cases it's possible to move the rocker tip very close to or even off the edge of the valve. This is what will happen as the pushrod length is increased in an effort to establish the proper mid lift geometry. People will stop well short of the optimum length because of this happening. Then things will start to go south as the guides are slowly pounded to pieces.

-=Z28=-

iTrader: (3)

Flow, Intake: 264cfm @ .500” lift / 28”
Flow, Exhaust: 180cfm @ .600” lift / 28”

I just got my retainers and noticed that. They are kinda small to do what was shown in the video. I can rig up something I'm sure. Yes, Need to make sure that roller tip is as centered as possible at mid lift on valve tip.

I cant find my adjustable push rods... hmmm

-=Z28=-

iTrader: (3)

Here, these are more complete,

Found these on Speed talk,

Dart 200 pro I

int ex ex. %
.200 129.2 114 88 %
.300 185.6 145 78 %
.400 229.3 164 71.5 %
.500 261.4 172.2 65.7 %
.600 252.5 174.2 69 %

skinny z

It's easy enough to rig up something that will lock in under the retainer where the surface is flat. I used that old caliper and it worked perfectly. I was able to maintain a perpendicular reference plane and take my measurements
I'll crunch those numbers and see what DynoSim cranks out.
Just information purposes, see if you can find out what the test fixture bore is. The flow numbers change quite a bit as the test apparatus bore increase. Eg. 4.03" vs 4.200".

-=Z28=-

iTrader: (3)

4" bore I believe.

Can I use my std valve spring height checker on my beehives and just add the stepped difference? I dont see why not...

How or what chemicals would you recommend to clean my alum heads? Pressure wash style.

Here is my install and open height's/ pounds,
Some of the labeling may not be accurate, I'm sure you will know what I mean. I'm wondering if I should shim a few /.015? or just run it.... Also, my machinist said to use the same valve to check seat and pocket variances and that will tell me if its the valve/locks that are off or the pockets and seats that are giving me the + or - .015 across the board.





Yes, please do, I am interested in seeing what it says! Thanks!

I'm putting heads together this weekend, Machinist said he will have my stuff by next weekend. Getting closer.

What oil pan do you run recommend? Been reading forums here yb etc and I'm looking at the canton 15-244. 2 things I dont like, Price and I have read changing oil filter is a pain... Thoughts?

Thanks again.

skinny z

I found the same flow numbers on Stan Weiss' website. He has a pretty good library of cylinder head data.
http://users.erols.com/srweiss/tablehdc.htm
If you're thinking about a .015" shim to bring up the pressures, personally I wouldn't be concerned. Remember that the conical spring will do the job with less pressure than a conventional spring. The small retainer also adds to efficiency of the package.
I have the Canton 12-244. There are no problems with a filter change. I'm using Hedman LT headers.
I have most of your data from your first post. There's no mention of your final compression ratio though (I know you're waiting to mock the engine up for measurements). As for the cam, I'll do one simulation with it installed straight up and another in at 4 degrees advanced. I'll also demonstrate what a change in headers will do. Dyno headers with open collector extensions vs chassis headers with a single muffler. It's an eye opener.

-=Z28=-

iTrader: (3)

9.84 with a .041 gasket, I may try to find a thinner gasket... What do you think?

Bore: 4.030
Stroke: 3.75
Deck Height: 9.010
Pistons: +6
Chamber: 72cc
Gasket: .041

Thanks.

-=Z28=-

iTrader: (3)

How was the fitment of those headers? 68468? Not sure what I want to do there yet... I have all the fab equipment, so I'm not worried about that. Its getting all the parts to fit.. Headers, oil pan, exhaust, new torque arm... etc..

MSgt Luttrell

I would try to use a thinner gasket and see if you can get to at least 10:1 compression, with the lobe separation of your camshaft being 110 degrees, you will need the compression or you could suffer from too low a manifold vacuum at idle.

I'm running 10:1 compression in my 383 with a camshaft lobe separation of 110 degrees and my manifold vacuum at idle is 13 on the gauge, just barely enough to operate power brakes; any less and I'd have to swap over to manual brakes.

MSgt Luttrell

I used a set of Doug's Long Tube Headers on my setup, so I can't say about the Headman's, but pretty much any set of long tubes on these cars are tight, very tight.

MSgt Luttrell

I used a set of Doug's Long Tube Headers on my setup, so I can't say about the Headman's, but pretty much any set of long tubes on these cars are tight, very tight.

skinny z

Using a .026" gasket, (Victor Reinz/Clevite 5647) pushes your compression ratio up to 10.14:1. Your DCR with the .041" gasket is 7.4 vs 7.64 for the thinner gasket. Both of those numbers are in the low range. I'd expect an under performer at low RPMs and poor vacuum as pointed out by MSgt.
Your machinist can guide you on whether you can run a .036" piston to head clearance. Even then, you haven't made up for the low compression ratio.
I see a couple of options.
1) Considering that you have the cam, you may want to consider having the heads milled. If it were me (and it is actually as I've pointed out I'm rebuilding the top end and adding a cam to my SBC), I'd have chambers reduced to 68 cc and run the .026" gasket (pending your machinist's approval). That brings your SCR up to 10.6 and the DCR up to 7.96. That DCR is about the midrange for a street engine.
2) You could also opt for installing the cam several degrees advanced. That will make up the poor compression and restore some idle vacuum. Four degrees advanced with 72 cc chambers and an .026" gasket gets your DCR to 7.9:1. SCR stays the same of course.

FWIW, there are more than a couple of individuals here that have run tighter quenches than .040". I've first hand experience with one. That's a ZZZ block that's .020" over with hypereutectic pistons. .010" deck and the 5746 gasket. Zero issues that we've been able to tell. 6500-6700 redline.

Keep in mind that your CR is only part of the build. In a 400 HP SBC, 1 full point in compression is worth about 4%. Doesn't seem like much but more importantly, it's the other aspects of higher compression that you're missing with a reduced CR. Driveability and fuel economy to name a couple.



You raise an interesting point and one which I don't have a hard answer for. I can relate a couple of experiences. One being my own build, which with the smaller cam, managed about 11" of idle vacuum. My SCR is low at 9.8:1. I have had zero issues with my power assist but that's my setup compared to yours. The differences may account for your 13" threshold. The engine I'm currently assembling, with a 288 cam and a relatively low compression ratio 10.2:1 (that cam would like 11:1) is basically the same iteration as what was installed in another chassis albeit with aluminium heads and a SCR closer to 10.5:1. It had closer to 8" of idle vacuum and yet still operated the power brakes satisfactorily. Every combination is little different though.

skinny z

As for the headers, the Hedman 68460 fit perfectly. Clearances to the starter (I use a mini starter from an LT based engine) and oil filter are excellent. No trouble at the crossmember either.
I fabricated a 2 1\2" stainless y-pipe and then modified my transmission crossmember to allow for as much ground clearance as possible.

skinny z

Hedman 68460 with the ball/socket collector cut off and 3-bolt flange welded on.




2 1/2" stainless y-pipe with a MagnaFlow 2x2.5" to 3" merge.




Modified transmission crossmember to get the y-pipe tucked up as far as possible.



The now rusty Hedmans and the somewhat smashed y-pipe mocked up in the new chassis (after several years of service in the old IROC). That damage to the y-pipe was from hitting ONE culvert sticking up through the pavement. There's 3" ground clearance at the lowest point.

MSgt Luttrell

It very well could simply be the difference in cam grinds, mine is a Hydraulic Roller Tappet, with a lift of .528” Intake / .536” Exhaust and a duration @ .050” of 221 deg. Intake / 226 deg. Exhaust; the lobe separation is 110 Degrees.

skinny z

Hydraulic roller as well. The old cam is .575"/.565", 224/230 @ 050", 274/280 adv, 110 LSA, 106 ICL. Very similar cams. I imagine the overlap is similar as well.
The new cam is .550"/.570", 236/242 @ 050", 288/294 adv, 110 LSA, 106 ICL. It also ran power brakes however that was in a Chevelle that belonged to a friend and perhaps his acceptance of brake efficiency differs from mine.
Altitude could play a difference (when comparing your vacuum to mine) as my 2500' elevation has taken about 1 -1.5" of vacuum away. Back at my 600' elevation house, vacuum was definitely higher. So was performance and fuel economy. Still my brakes are a OK at 11" or 12" on a "good air" day. Could be a difference in brake booster or any number of braking system combinations.

All of that said, you do raise a valid point and something the OP will have to consider. Especially, as you point out, if he keeps the CR low.

-=Z28=-

iTrader: (3)

Thanks guys,

I talked to my machinist and he said he would prefer milling heads more, than running a .026 and keeping my quench closer to .040. I can drop them off on Tuesday if I choose to go that route.

Another option is new bare heads......

I have a lot to think and read about now.

Again, thanks.

-=Z28=-

iTrader: (3)

What if I got some flat top pistons? That would get me 10.48 and 7.84.

If I went with 9910HC30 pistons, (-4cc) that would get me to 10.96 and 8.19.... I think the pistons, 200 bucks will be cheaper than having heads milled...

or these, HRC840342405, -5cc 11.09 and 8.29.

What elevation did you use on dcr? I'm 952'

Thanks again.

Dan

MSgt Luttrell

Milling the heads down to get the necessary CR is a great idea as long as your machinist is in on what you are trying to accomplish, I wouldn't hesitate to go that route.

-=Z28=-

iTrader: (3)

MSgt, after much thought, I agree with ya. He said no problem. Tuesday I am bringing them up to him. I just need to figure out how much to take off.

If I can get them to 68cc, run a .030 gasket, that gets me to 10.51 and 7.86.

If they can be milled to 66cc, run a .040 gasket, that gets me to 10.5 and 7.85.

If milled to 66cc and run a .030 gasket, that gets me to 10.75 and 8.04.

I'm not sure how much can/needs to be taken off to achieve the one I choose. Anyone know? Like .025 = how many cc's.

In the mean time, I found my adjustable push rods, and I am going to study up on resurfacing heads and what values equal what.

Thanks for the reply.

Dan

-=Z28=-

iTrader: (3)

This is right from dart...

Milling: Min. 58cc = .060” (.0065” = 1cc) Flat Mill

Angle mill .125” safely / .200” = 49cc 1.5° (carefully)

So I believe I have some options. From my understanding, I can safely bring these down to 62cc, which would get me 10.96 and 8.19.

I'm open to suggestions.

skinny z

If my approach is of any benefit, what I'm doing in my own build is:
Target the .040" quench.
I've optimized my SCR as much as I could by way of milling the heads. I went to the practical limit as advised by my machinist before I would get into the trouble of having to get the intake manifold milled too. That limit got me back to a 65.4 cc chamber. Previous work on the chambers opened them up to 68 cc or so.
What I couldn't make up in SCR, I addressed by way of advancing the cam. Closing the intake valve earlier in the cycle by 4 degrees has raised my DCR from 7.82 to 8.08. SCR stayed the same at 10.2:1.
You could follow much the same recipe.

You HAVE flat top piston now don't you? The Speed Pros have a 5 cc valve relief (mine did).

-=Z28=-

iTrader: (3)

Yes, flat tops. I'm going to do the milling option. i just need to figure out what scr and dcr I want. I think I'm going to have them milled to 65cc

Bore: 4.030
Stroke: 3.75
Deck: .010
Piston: 5cc (going to cc to make sure, cant find info on them, h600p)
Gasket: .040
Head: 65cc

That gets me 10.74 and 8.03, Which I have read and been told are great numbers.

Thanks

D

skinny z

Good numbers to shoot for .
It would be nice if you could get your quench less than .050". It's a hedge against detonation, if the piston to head clearance can be kept closer to that .040" number. Problem is, any gaskets that I've seen that are .030" are 75 bucks...each. There's an economically priced Mr Gasket Ultra Seal at .028". That'll put you as .038" ( you mentioned you were going to double check your piston deck height to confirm .010" down). Maybe you'll find room for the VR 5746 gasket at .026 or this Ultra Seal at .028. (Both less than 25 bucks each).
If you CAN get your quench down to .040" then a 67 cc chamber will get you 10.74. That may keep you out of having to get your intake milled.

-=Z28=-

iTrader: (3)

LOL, your right, I meant to adjust for that... Yes, .040 quench is what I'm shooting for!
I think .038 will be just fine... I will run it by my machinist.

Yes, confirmed I'm .010 in the hole.

And confirmed pistons are +6cc's

-=Z28=-

iTrader: (3)

K, so here are my final 2 options I've boiled it down too.

bore: .030
stroke: 3.75
deck: .010
gasket: .028
Piston: +6cc
Heads: 66cc

Static compression ratio of 10.8:1.
Effective stroke is 2.78 inches.
Your dynamic compression ratio is 8.07:1 .
Your dynamic cranking pressure is 160.78 PSI.

or

bore: .030
stroke: 3.75
deck: .010
gasket: .028
Piston: +6cc
Heads: 67cc

Static compression ratio of 10.68:1.
Effective stroke is 2.78 inches.
Your dynamic compression ratio is 7.99:1 .
Your dynamic cranking pressure is 158.72 PSI.

Now I just wonder if I'm going to have piston to valve problems...

MSgt Luttrell

Those compression numbers look a lot better and should make that camshaft happier. You are going to have to double check the valve to piston clearances after you get the heads milled.

skinny z

Using your advertised duration values of 293.2 and 296.7 along with 67 cc heads and an .028" x 4.130" gasket:

https://www.summitracing.com/int/par...make/chevrolet

I get 10.67 SCR and 8.02 DCR with a dynamic stroke of 2.72".
66 cc heads yield 10.78 and 8.1.
Close enough to yours.
It's splitting hairs at this point. If PV clearance allows (You should be able to check ahead of time. I prefer the checking spring and dial indicator/degree wheel method over the clay method), I'd go for the 66 cc chambers. I think that cam is going to need all the compression you can give it.
I'm still surprised at it's advertised numbers vs. it's .050" duration values.

-=Z28=-

iTrader: (3)

I'm thinking the 67cc, soley because, my machinist has my pistons.... I figure, .032 milled off couldnt cause me any ptv problems because Im .010 in the hole and a .028 gasket.....

I dont know.... I'm going to spend some time talking with him tomorrow and If we come to the conclusion I will be okay, then okay, Otherwise I can grab a rod and piston, hopefully, and check and see what clearances I have and call to let him know what to mill. My gut feeling says I will be fine.

But I'd better grab a rod and piston, if hes done with them, and check. Yes, I will use the dial indicator and soft spring. maybe I can do it by setting the head on the block, spinning in a few blots, flip the block over, move valve its full lift and try to measure from the bottom up in the cylinder.... i bet I can figure something out like that.

I dial bore gauged my bores yesterday and everything looks great. Within .0005 round and all within .001. No ring at the top, and pits in bottom of #8 are .0005 deep. I'm running it just the way it is.

Just talked with machinist, and he highly doubts there being a problem. I'm going to bring some measurements with me and we can get a good idea. So if possible, I'm going with the 66cc.

I'm so wishy washy. Those of you following along can avoid my uncertainty by making sure everything fits as MSgt stated in his first few posts.

I have built a few engines, nothing like this, and am learning a boat load.

Special thanks to skinny, orr and MSgt for the guidance with this build. I still have a way to go and much to learn.

Thanks again.

skinny z

With the clearances that are expected, it might be possible for a visual check.
15, 10 and 5 degrees before TDC for the exhaust valve and 5, 10 and 15 after TDC for the intake. I'd think you would be able to push the valve into the piston at those test intervals and actually see that you have more than a 1/10" clearance. If it's too close to call, then out comes the dial indicator.
Your machinist sounds like a decent guy. It'll especially helpful to be able to bounce ideas off of him and get some reasonable feedback.

skinny z

You may find these interesting.
383 c.i.d.
Dart Pro 200 heads
Hydraulic roller, 293/297, 232/233 @ .050", .545"/.547"
10.8:1 SCR, 8.1:1 DCR.





Small tube headers with mufflers. Cam installed straight up.




Open (dyno) headers. Cam installed straight up.

skinny z

Same combination but with cam advanced 4 degrees.




Small tube headers with mufflers. Cam advanced 4 degrees.




Open (dyno) headers. Cam advanced 4 degrees.

-=Z28=-

iTrader: (3)

THANKS!! Now you have me curious as what the dyno will reveal....

They are pretty similar eh? Power comes on a tad sooner advanced... What are your thoughts?

Thanks so much for taking the time to do that! Very cool.

Other news, Heads are at the machinist. I'm going with 66cc. He very kindly took some of his time and showed me how far out of wack the valve seats are. Some were .009 out of round!! So... he is going to fix them and redo the valve seats, knock some of the "ski jumps" down, lol. He said the seat angle transitions are too big. Showed me what they should look like and its a no brainier.

He is also going to go through the guides. Some were horrible, And is also going to re grind the valves. Remember folks, these heads only have 1500 miles or so on them... I will never buy assembled again. QC is horrible.

It was such a privilege to get to go on the other side of the chain, and walk through his shop. I get the feeling not everyone gets the experience.

Again, Thanks for running the numbers. Honestly I thought I would be closer to 500. But then again, everyone thinks they have more than what they really have. :0

D

skinny z

I had heard of QC issues with Dart although I have only one experience with them. That wasn't a pleasant one but it was an on-line reseller who was to blame for the poor assembly. As for your 500 HP, despite your cam's large advertised duration, its no larger than Comps XR288HR. That cam has a 288 adv. duration and yet 234 @ .050". It tops out in a 350 around 6500. Put that in a 383 and you're closer to 6000. I'd have to double check but I would think that 500 HP out of a 383(na) is going to take closer to 7000. That would need a hefty cam (maybe 240
@ .050") and bigger heads.
I had said that your machinist seemed a decent guy. That's almost as important as having a doctor that you trust.

skinny z

Regarding the cam advanced vs straight up: Both your engine and my own don't show any appreciable gain with the +4 degrees option. Perhaps the 4 degrees of advance ground into the cam is making up the difference. It may be that the SCR/DCR relationship is decent enough so that we're getting what we can with what we've got. I've got some tech papers (and magazine articles) on some dyno testing and cam advance. I'll have to look those up to see what the results were. I don't recall anything spectacular.
In my case, because of my altitude and generally poor air for racing (or street driving for that matter), I've elected to install the cam on a 102 ICL rather than the 106 as indicated on the cam card. I want as much idle vacuum as I can get out of my combination and unlike you, I don't have the compression ratio I'd like for the cam I'm using. In your case, I don't see much of an advantage with advancing your cam although there may be some benefit in idle quality and mileage. If I remember what you had said earlier, you want as much HP as you can get with what you have. Straight up will deliver that over advanced.

MSgt Luttrell

Those are some very good numbers and a third gen is a lot of fun with that much horse power and torque, mine dynoed at 426 hp and 452 ft lbs of torque.

skinny z

I'm curious as to specs of that engine MSgt.
I'll be thrilled with 1.1 HP/C.I.

Looking at the dyno simulations posted, it's easy to see the huge difference the exhaust system makes. Open header horsepower is not easily duplicated once the engine is in the vehicle and outfitted with chassis headers and a full exhaust with mufflers. I always temper my simulations by going with the small tube headers and mufflers when selecting the various input values. Interestingly, my actual 1/4 mile ET and MPH results (used for estimating HP) closely match the simulated numbers once I've crippled my (simulated) engine with poor exhaust. Even as interestingly, I have a poor exhaust. Despite having mid length headers (they're not really long tube even though they are described as such) there's only a single 3" to a poor flowing single muffler in the OEM location. It crushes performance. Cut-outs at an appropriately placed location along the collector are on the list. Something I'd suggest to anyone who is restricted to the typical cat-back arrangement but wants to build as much power as possible at the track.

-=Z28=-

iTrader: (3)

Some more goodies.

MSgt Luttrell

Here are the specs on my 383

Compression Ratio: 10:1

Block: Cast Iron, 1 piece rear seal, 4-bolt main caps with passenger side oil dip stick hole, brass freeze plugs.

Crankshaft: Cast Steel, polished, stress relieved and shot peened with chamfered oil oils (scat I believe)

Connecting Rods: Heavy Beam with 150,000 psi bolts

Pistons: Hypereutectic Aluminum

Camshaft: Hydraulic Roller Tappet

Cam Lift: .528” Intake / .536” Exhaust (.558" Intake / .566 Exhaust with 1.6:1 rocker arms)

Cam Duration @ .050”: 221 deg. Intake / 226 deg. Exhaust (241 deg Intake / 246 deg Exhaust with 1.6 rocker arms)

Lobe Separation: 110 Degree

Cylinder Heads: Performance Aluminum (Blueprint H8002K)

195cc intake/75cc exhaust runners

Combustion Chamber: 64cc

Valves: 2.02” Intake/ 1.60” Exhaust

Rocker Arms: Aluminum Roller, 1.6:1 Ratio

Valve Springs: 1.25” Diameter

Balance: External

Ignition Timing: Base 14 degrees BTDC, 34 degrees total

Aluminum Dual Plane Performance Intake (Edelbrock RPM Performer)

Holley 750CFM Carb with manual choke

HEI Distributor

700r4 TCI transmission and a Hughes Street Master 2500 stall converter.

My exhaust system is a set of Dougs long tube headers with 1 3/4" primaries, 3" collectors, into 2.5" dual exhaust, with Flowmaster Super 10s dumping in front of the rear axle.

skinny z

That's a tried and true exhaust system. Same thing I had on my first hot rod (waay) back in the day. If the lengths are right (depending on the type of muffler used), it can almost reproduce the results of open headers. There are few computer programs that will calculate the appropriate length of collector extension for optimum torque or horsepower. The PipeMax program I use will give examples right to the tip of the tailpipe. I'd like to add cutouts as I mentioned. With my Camaro dropped about 2 inches, ground clearance for mufflers before the axle isn't the greatest.

MSgt Luttrell

I'm good to go as long as I avoid speed bumps, I have a nice set of air shocks for the back; if I'm going to have a couple of passengers I add a little air to them and don't have any problems. It's the price to pay to get all the horse power you can out of them. Here is a pic of how I ran the exhaust, it has SLPs on it in the pic, after I swapped in the 383 I changed the mufflers over to Flow master super 10s.

-=Z28=-

iTrader: (3)

Nice MSgt. Ive thought about something like that. On a scale 10 - 1, how bad is the resonance in the car? I'm planning on hitting up the local exhaust shops to see if I cant dig through their bin of exhaust leftovers, mainly for angles, etc, to ease my installation. Otherwise I will just order a kit for angles and bends. But def fabing my own set-up.

Thanks for posting your build and sharing exhaust pics.