firehawk1724

I was referring to the 350 tpi numbers you posted I assumed you would've followed but I do agree my statement was a bit ambiguous and loose in structure..... now all I've ever heard was aluminum heads disipate heat faster than iron heads thus allowing more hp...is that true? I'm just asking for knowledge I understand ur setups are specific to produce the numbers you've obtained.

stealthroc89

Do you think a HSR on the 350 Vortec build would have a negative affect? Would the HP gain be worth the TQ loss?? I'm sure a bigger cam would do better with the HSR but I'd like to know what a smaller cam can do with that intake.

Atilla the Fun

Yes, aluminum dissipates heat faster, but at 6000 rpm, you have about a millisecond between burns to dissipate that heat...! Iron retaining heat actually makes slightly more power. The heat is the expansion. The expansion is the pressure on the piston.
Aluminum does get by with slightly higher compression in street engines, because they don't stay at high rpm for any length of time. That is worth a little extra power, so it comes out about even with slightly lower scr iron heads, assuming identical everything else.

Atilla the Fun

The HSR is sized right for 2500-6000 rpm on a 350, with 180 cc heads. This a cam like the GMPP LT4 HOT is a fairly good match for such a combo. The ZZ4 cam wouldn't be bad, either. If you want an even smaller cam, then use long-runner TPI.

skinny z

About as good an explanation as I've seen.
Nice to see you back.

63bravo!!

welcome back atilla how are you doin?

63bravo!!

btw still patiently waiting for bb numbers i might have missed um if u already posted them i appolagise. if i can find a 454 in good condition, whats a good head/cam combo, same for 496, and 632 eventualy. btw i will be going with coil on plug ignition and mpfi and gertting a dyno tune. also im thinking about trying to find a place that will build me a t56 with the 5th gear ratio in the place of 6th (so when in 6th it would have the same ratio 5th used to) and then making 5th 1:1 and lower 1st gear/ change the rest to maximise acceleration(i dont even know if this is possible just an idea i had)

Primetime91

iTrader: (15)

I already PM-ed you the big block numbers, unless I missed something? I know I didn't give you the horsepower #'s through the whole RPM range, but with the torque numbers you can calculate them easily with the formula: HP = Torque x RPM / 5252

As for your transmission gearing, check with a company like Liberty Gears, they may offer true road race ratios like what you seem to want for the T56

And it is good to see you back Atilla, even if it's only for a little bit

ChainHartMachin

This build is already "built" about a year ago. So I'm looking for constructive feedback.

355 w/ AFR 180cc Eliminator heads (regular ported, not competition)
HSR for the intake manifold
1.6 intake/ 1.5 exhaust roller rockers
Comp Extreme Hydraulic Roller 270 / 276 advertised, 218 / 224 @ ".050, 108 LCA installed 4 degrees advanced
Cast steel crank, aftermarket rods
LS1 injectors
Hedman 68460 headers into 2 1/2" true duals with dynomax ultra flow welded mufflers
Stock converter and 3.27 gearing (w/ posi)

The idle is lopey, so I run it at 850 rpm to smooth it out a bit. I have no complaints about off-idle torque and I almost always loose traction at the top of first gear at WOT.

Atilla the Fun

PM Primetime91 for the 496 dyno results and parts combo, I still haven't found my file. As for the T56, you're looking the wrong way for your desired results. not even Rockland standard Gear offers what you want, you'll need to go with the Richmond 6-speed. You're not limited to just the advertised ratio sets, they have others that aren't advertised, and the design allows mixing and matching.
Regardless of advertised torque ratings, the R.O.D. IS stronger than the T56.
Also, Just because I can find a few minutes to type doesn't mean I can resume progress on the big brake kit, or the axle swap.

Atilla the Fun

It seems slightly mis-matched. Not dramatically so, but not ideal. What are you wanting it to do differently? Better idle? More mid-range?

Atilla the Fun

Thanks, I'm not really back at the hobby, I'm still on hold for a few more weeks.

63bravo!!

Lol i probably shouldnt post after 12 hrs of work and then 3 hrs of driving i completely forgot about the pm thx again and i will look into the rod

ChainHartMachin

I realized I forgot a couplespecs... 9.8:1 static compression (that's assuming 65 cc heads, but it could be higher since the heads had to be surfaced to remove brinneling marks), about 8.1:1 dynamic. .542 / .502 lift

The main thing I'm wondering about is that it's in front of a 700R4 which has a pretty steep RPM drop from 1-2. Would a closer ratio transmission like a 200-4R or even a T56 be a better choice?

Also, would running something like Rhoads fast-leak down roller lifters on the exhaust valves only be a reasonable way to cut overlap at lower RPM such that emissions testing is a little easier?

63bravo!!

ok guys im back i did some calculating when i had some vspare time in the motor pool today and i think im close to the ratios i want for my trans i probably should make a new thread in the tranny section but i figured yall already have the full scoop[ on what im going to be trying to do so here it goes
1:4.06
2:2.22
3:1.57
4:1.24
5:1
6:0.76

rear:3.07
tire O.D. :26"

tell me what you think its my first time doing this so im wayyy open to sugestion

Primetime91

iTrader: (15)

I'm interested in the Rhoads lifters too, I've never really heard anything about them good or bad, curious if they're any good.

As for passing emissions.... try the "dry gas" method, if you're not above cheating the system a little bit and you just need a little extra help

Atilla the Fun

I'd change the cam, but the Rhoads lifters will help a little, as would swapping on a set of Howards 1.3:1 rockers for the testing.
The 700R-4 rpm drop is not 1.625 divided by 3.059 times redline. That forgets to account for the torque converter. Yes, a 200-4R would help, but you might start with a custom converter instead. Besides, those companies typically do one free re-stall, which I would save for later, in case you do go to 200-4R, because CPT can do you a 200-4R with a 30-spline input shaft.
Going to a fully built T5 would be best, but not cheapest. A serious T5 can hold 600 HP and 500 ft-lbs, and is the lightest such trans. But even a TKO would be better for performance than a T56, due to weight.
Manuals have an inherent advantage in not having a built-in high-pressure fluid pump inside, so expect about 9% more RWHP if you swap from auto to stick.
Sticks are best for roll-racing, road racing, drifting, et cetera.

Atilla the Fun

You do NOT want a 12:1 effective combined first gear with a big-block in a sports car. Even with a pair of drag slicks. With that rear gear, a 3.27:1 first in the trans would be really pushing it.

63bravo!!

im guessing it would kindof just spin them no matter what? the lowest ones richmond has on the shelf ae 3.28 and 3.04

Primetime91

iTrader: (15)

Just to illustrate what Atilla said:

With a 4.06 1st gear ratio, and 3.07 final drive ratio, you get a total torque multiplication of 12.46

Suppose your big block puts out 600 lb-ft of torque at the flywheel (Which that 496 does)

Multiply that by 12.46 and you get... 7,476 lb-ft of torque! (Not factoring in drivetrain losses yet, figure somewhere around 14% +- for a manual)

Your biggest gains will be in keeping the ratios closer, especially in 3rd-4th-5th

63bravo!!

ok gotcha my 2 through 6 gears look pretty close (like i said though im new at this) so a 3.08 1st would be best? btw i know im going to sound a little crazy and immature here but i would like it to pull the front wheels off the ground some

63bravo!!

i dont want to crowd atilla's thread though so im going to start a new one in trans forum will be titled "help choosing gears for tranny for orr"

firehawk1724

Ok so I gotta ask the 350 build for the 425hp are the stock pistons capable ofproducing the power or is there a specified type of piston needed to be used? I did read that u said if specified parts were not listed then doesn't affect the numbers but I just wanna be sure so I'm asking

Atilla the Fun

That build would be best with tight-fit forgings, of 4032 material. Loose-fit forgings are 2618 material. If you take every measure to never have any detonation, even inaudible, then cast pistons will suffice.
The material of the pistons has no real effect on power, but that combo is right on the verge of detonation, across the entire first half of it's rpm range, and how the pistons are made will determine if the engine survives a tank of bad gas and a knock sensor failing at the same time. Not likely, but possible.

firehawk1724

Ok so next will the 700r4 I have in the car handle this engine build? I was really planning on converting to a stick if I do so is there any real difference between a T5 and a T56 besides the T56 being heavier?

Atilla the Fun

It is possible to get a T5 built to survive this engine, but the cost is up there. The T56 is already strong enough, and seems to have everything going for it, but a TKO600 is lighter than a T56, cheaper and stronger than a built T5.
If you run an automatic, your RWHP should be about 78% of your crankshaft HP. If you go with a stick, that improves to about 87%.
Any '88-'92 700R-4 can be built to take 620 ft-lbs.

firehawk1724

Wow didn't know the difference was that big...i'd rather much have a stick so I will try to find a tko6.. thanks a lot well I guess know I must find and assemble necessary parts. I live in michgan so by spring I should be ready to burn up the streets a little...do you urself have any of the parts for sale the camshaft, heads, etc? Or know of any good places to find used?

EFIhead

I have a quick question about the high torque TPI 350 build. What would need to be changed for it to run on midgrade and how much power would be lost for that? Also one more thing, why is it more fuel efficient than 383?

87tpiz28

iTrader: (2)

How well would this cam perform on the 350tpi set up?
LPE 219 CAM, 211/219 .530/.560 LSA112

firehawk1724

Ok Ijust got a vortec motor out of a 99 tahoe...I think I'm going to closely model the 350 tpi build.......my question is I read that the vortec heads have a restrictive lift.. is that true? And will limit performance

Primetime91

iTrader: (15)

This will explain the vortec head's stock lift limitations, and what you can do about it. It's not so bad, just some machine work

http://www.chevyhiperformance.com/te...ift/index.html

five7kid

iTrader: (14)

Link isn't working.

Stephen

iTrader: (12)

Or with no machining required, you can drop in beehive springs and increase the stock available lift from .450 (most people will tell you .460 but the .0.0 is the safety margin) up to the beehives .550.

http://www.carcraft.com/techarticles...ade/index.html

Primetime91

iTrader: (15)

http://www.chevyhiperformance.com/te...ift/index.html

Working now? The link above worked for me, wierd.

That beehive spring thing is interesting, that's the first I've ever heard of that

five7kid

iTrader: (14)

Hmmm, both links seem to be working now. Weird.

I like the beehive springs, but I'd still tend to go ahead and cut the guides for the better seals.

Primetime91

iTrader: (15)

I would tend to agree with you. Then you are also using valvesprings that you KNOW are correctly matched to the cam you are running

Stephen

iTrader: (12)

Beehives have been around for a few years & as long as the spring rate is correct, I don't see any issues with them being reported. Anybody else hear of beehive failures, that would have been prevented by using "standard" springs?

And the beehives can be installed at home, in your driveway, in an afternoon. No disassembling the top end, pulling the heads, getting them to a machine shop, then having to reassemble the top end, like the older method.

five7kid

iTrader: (14)

I had plans in work with a set of 062 heads - had a shop tank the heads and cut the top of the guides, cut the exhaust valve seats for 1.60" valves; I bought Manley valves to put in and L92 beehive springs with positive stem seals to install upon assembly after I ported them. Those plans were detoured when I found an LS1/4L60E drop-out and I sold the heads/valves/seals and used the L92 springs on the LS1.

Grumbles

The springs you recommended in post 9, is that a set of 16?

five7kid

iTrader: (14)

I believe the answer is "yes", but you could call CP to ask them directly.

BrandonSB

what happened to atilla ?!

killa66cam

I am wondering this also. If anyone has any info, please share. I haven't been on in a while.

For those dead set on doing some kind of modifications to the 305, you can check out a thread that I started a couple of years ago. It is in the general/engine tech forum, called 305 - questions and suggestions...or something like that. Atilla pretty much made all of the recommendations. Pay attention to what Atilla posted, and not much else in there. He would never advocate the building of a 305 when you can get a 350 and build it better for less money; but hey, some of us are hardheaded...finger pointing at myself!!! Just posting this information up for people to look over and contemplate.

Cam

TheDarkMinister

N.J.-SLICK-1

The Horse Power on this 400 build up seems a bit high, but the torque seems in order, I figure approx. 475-485 tops with this build up, but thats nothing to sneeze at and a joy to drive, this is quite simular to mine but I have flat top pistons, 6in. rods, and Patriot Performance 185cc Vortec heads, smaller 1-5/8 hedman hedders, with a 950 HP holley, turbo 400 trans, and 3.73 posi! Hell maybe I need a better set of headers huh?lol!

scott13676

iTrader: (1)

what did they use for a prom on the 350 TPI build? thanks,scott

Guest

You figure? Versus what he dyno'ed? Refer back to the first post, you'll see that's why it's here: it made outstanding power considering the parts / cubes / cost.
And as he also noted, change anything at all, your results will likely be less.

Orr89RocZ

iTrader: (20)

YOu could use the same exact parts and the results could be more or less... the machining on the block, ring quality, how the motor was broke in, etc all play a role on power production, not just in the parts. If the block was bored at all without a torque plate, the cylinders could be out of round, causing terrible ring seal. A well machined block could make 5-10 hp more just from machining alone!

Marchosias

I agree with what Orr says about the machining/rings/assembly.. many factors will determine the outcome @ the dyno..

I'm taking on the 383 TPI build and duplicating the numbers (coming close to them if lucky) that Atilla posted will require more effort that what I tough..

At 5000ft... like ronnjonn told me yesterday the torque will come down 531 to something like 440

It would be great if Atilla was around to ask him what altitude was the engine dynoed

Orr89RocZ

iTrader: (20)

If the dyno has corrected numbers, it shouldnt matter...it should correct to sealevel so all engines have a base standard to go by.

Guest

Considering the claimed results, and considering Atilla's claims about being a pro machinist and a pro builder, I would think it safe to assume that every "trick" and detail were taken care of. Probably used gapless rings, too.
But as to boring with torque plates? Fail, IMO. The plates are for honing. And I've never seen that tested as being worth more than 2-3 HP, which can be the normal variance in dyno pulls anyway.