paulmoore

Well, my old motor is garbage, and I now have a 383 stroker on its way. I'm looking to achive 500HP/500TQ with it. here is what I am looking at now...

383 short block 4 bolt main, cast steel Eagle crank, medium grade Eagle forged SIR I beam rods, flat top hypereutectic pistons, moly rings that have been file fitted, the cam specs are 235/240 @.050 with .333/.340 lobe lift/.533/.544 valve lift using 1.6 rockers 112LSA that is degreed with a true double roller timing chain, compression would be 9.6:1 with 76cc heads / 10.9:1 with 64cc heads

The short block normally comes with a new flexplate and a balancer, but I already have a Fluidampr, and my car is a stick so I told them not the put those on, and internally balance the rotating assembly instead.

The heads that I am looking at using are Dart Pro 1 aluminum units that come with 230cc instake runner ports 80cc exhaust runner ports, 2.08 intake and 1.60 exhaust valves, either 64cc. 72cc, or 76cc combustion chambers. I plan on using the 72cc version to lower the compression to around 10.2:1

I also plan on re-using my Edelbrock Performer RPM Air Gap manifold. It seems to be the superior dual plane intake manifold on the market, and when compared to the single plane intakes, there is only a loss of about 5-6 HP, but makes up for it with higher TQ production at a lower(read streetable) RPM. Also, the guy who is building my short block said I might want to look into getting rid of the Edelbrock 750 CFM carb and getting a Holley 750DP for tuneability. Now I'm not sure if I want to use the camshaft that comes with the short block, maybe I'll look into a COMP or other similar camshaft after the whole thing gets here. So what do you guys think???

F-BIRD'88

Heads are too big for the cam duration and rpm range you want. I'd get the smaller 215's and mildly clean up the ports. In order to get lots of torque in the mid range you need high port velocity. 230cc intake ports are too big for this one. The 215's will come up nicely in flow with mild porting. the "out of the box" spec is just a starting point.
Dart casts their heads for durability and casting integrity.
they are intended to be cleaned up by the builder. (Porting) EG the valve guide bosses are huge in the port as cast. need profiling. You won;t need to remove a ton of material to get what you want.
I'd look into a custom ground solid "street roller" with lots of lift .600++and short duration 235-247@.050.

88IROC350TPI

What are your plans with this motor? Daily driver? street/strip? Those heads are definately way too big for the rest of the motor. F-BIRD'88 is very correct in that Dart Pro 1's aren't nearly as good as they should be right out of the box and for that reason I wouldnt buy them. If you're just looking to build a mean street car I'd focus on low/mid-range torque... something that isn't going to be easy with 230cc heads. Me personally, even with a 383, I'd go even smaller than 215cc... Something like Canfield 200, Trickflow 195, or AFR 195's. As for a cam you didn't specify what kind you planned on running? Hydraulic, hydraulic roller, solid, solid roller? what?

Also... dont skimp out and buy hyper pistons. Get a set of TRW forged flat-tops and call it a day... You never know down the road what you may do with your motor so might as well build it as solid as possible while its out of the car.

joe383

I would use the world sportsman II heads I just got a set from Jegs I think they were $560. I think even 215 are too big for the cam and intake you plan on using. I am building a similar motor but it is a 331 the only reason is I have a new steel crank for a 327 still in the box. When I started buying all my parts I was planning on building a 383. I plan on using comp cam XR268R it’s a solid roller profile 268*/274* advertised 230*236* @0.050 .552”/.564” lift with 1.5 rockers and a 110* LSA and having the heads pocket ported, 10:1 compression, timing belt, electric water pump, performer RPM air gap intake, demon 625 carburetor ect.ect. On a 383 I think this would make 450+ HP on my smaller motor I am guessing I will make 400+ HP but plan on using a performer NOS kit from Edelbrock with a 75 HP shot. This setup on a 383 would make huge torque and be great on the street or strip. The cam has a huge power band which is important for a stick 2,000 to 6,000 with 3.73 gears this set up should pout you around mid 12s if your suspension is set up good.

paulmoore

F-BIRD'88: I'm not set on any particular brand of cylinder head just yet. I'm still looking at other companies. I really don't want to have to spend $1200+ for a set of heads, and then send them out to be ported for extra $$. I'm really running short on time (I live in a Civic Association and they don't like to see cars that are *inoperable*. And trust me, they will know if the car doesn't run, it's a long story!) Essentially what I need is to be able to get the short block here, and slap the heads on and reassemble the rest of the engine as quickly as possible. Who would you recommend for heads then? If I should use a 215cc runner, then what about AFR? They make very good stuff, and I shouldn't have to mess with any port work, right? As far as the camshaft, I don't know. I really don't need the high RPM capabilities that a solid flat tappet cam will give. Plus I would be having to set the lash all the time. I have no qualms about using a hydraulic roller camshaft/lifters except that they are expensive but there is no break in issues plus they have quicker ramp up rates. See, what I am worried about the most is piston to valve clearance. I just pulled the driver's side head off of the old motor today. There was definite contact with the pistons on cylinders 1,3, and 5, and they were all on the intake side. None of the exhaust valves hit which is weird because the exhaust has higher lift and longer duration than the intakes do. Needless to say, the block was squared .010 and then decked an additional .010 for a deck height of 9.005 in. Piston deck height was 0. So my intake valve hit with a .488 lift 234 duration cam! And my pistons had valve reliefs in them. If I were to use the camshaft with specs that you suggested, wouldn't I have some MAJOR valve to piston clearance issues? I would think that it would be safer to run less overall lift, but add some more duration to get the mixture in the cylinders. Pardon me if I seem a bit skeptical, but I'm worried that this might happen again. And I sure don't want it to happen again seeing as how I am spending another butt load of money on this new engine.

88IROC350TPI

Sportsman II's assembled with 1.437" valve springs cost $959 at Summit. Spend $140 more and you can get aluminum Canfield 200's from Competition Products... and get free shipping. I believe they also have a package-deal thing where you get Canfields, Professional Products hurricane intake, and valve covers for like $1199

If I were to buy heads I'd definately be buying Canfields. I've seen a lot of cars fly with them right out of the box.

paulmoore

You know, now that I think about it most of the stroker engines out there that I have seen have been making those huge numbers with some type of roller cam. Take a look at this one by strokerkits.com...

383 cid Small Block Chevy Package
AFR 195cc Street Heads
9.5 to 1 Compression
1 3/4” Headers
AFR FloPower RPM #5028 and 0-4779 750 cfm Holley Carb
Comp Cams Hydraulic Roller Cam #12-433-8
MSD Distributor 36° Timing
93° Octane Pump Gas

The dyno chart for the 383 is the one on the left...



The specs on the COMP Cams camshaft is..
Camshaft Specification Table
Part Number 12-433-8
Engine 1955-1998 Chevrolet
262ci-400ci
8cyl.
Grind Number CS XR288HR-10
Description

--------------------------------------------------------------------------------

Intake Exhaust
Valve Adjustment 0 0
Gross Valve Lift 0.52 0.54
Duration At 0.006 Tappet Lift 288 294

--------------------------------------------------------------------------------

Valve Timing At 0.006
Open Close
Intake 38 70
Exhaust 81 33

--------------------------------------------------------------------------------

These Specs Are For The Cam Installed At 106 Intake CL
Intake Exhaust
Duration At 0.05 236 242
Lobe Lift 0.347 0.36
Lobe Separation 110

--------------------------------------------------------------------------------

Recommended Valve Springs 986-16

F-BIRD'88

Valve to piston clearance has nothing to do with valve lift. When the valve is a t ful lift the piston is more than half way down the bore. Valve to piston clearance has to do with valve opening at and near TDC ( overlap, duration and cam phasing) the critical area is as the piston approaches and moves away from TDC during overlap. 30deg either side. If you are experienceing vale to piston clearance with a 234 deg cam something is wrong. cam installed overadvanced, severe valve float.

paulmoore

Well, I called the machine shop back today and spoke with the guy who is going to be doing my engine. I decided on using a forged crankshaft, rods and pistons, as well as retro fitting the block for a hydraulic roller camshaft. I am going to use the COMP cams 12-433-8 and step down to a 215cc intake runner size on the heads to keep the port velocity up as suggested earlier. This way, I can make less power on the street but I will be able to spray it at the track and not have to worry about blowing the motor up again.

paulmoore

Yeah, that's pretty funny that I'm quoting myself. Anyway, I talked to a few companies today, and have finally decided on using the AFR 195cc Street heads. They come with CNC porting and don't need any additional work. I have come to terms with the fact that I may not acutally hit my initial goal of 500HP/500TQ, but I'm OK with that. I feel that it might make it a little bit easier to drive on the street, but should still perform well at the strip. So my new combo will look like this...

1. 383 short block with a 4340 forged steel Eagle crankshaft
2. Forged Eagle SIR rods
3. Forged SRP pistons
4. AFR 195cc Street Heads
5. COMP Cams Hydraulic Roller Camshaft Grind #CS XR288HR-10
6. COMP Cams retrofit hydraulic roller lifters
7. COMP Cams 1.6 roller rockers(not sure which ones yet)
8. COMP Cams custom length pushrods hardened for use with guideplates
9. Reuse my Edelbrock Performer RPM Air Gap intake manifold, Edelbrock 750 CFM manual choke carburetor(unless I can't get it tuned right then I'll switch to a Holley!), Hooker Super Competition Long tube headers 1 3/4 primaries, and everything else that I originally had on the other motor.

If I can get 450HP/450TQ or 460HP/460TQ out of this combo, I think that it will still be a good overall performer

iroczracer07

iTrader: (2)

The A.F.R.'s are good, but if you're really going to buy them, why not buy the competition heads? They'll get you your 500 horsepower easily with the right cam choice. Call comp and tell them your suggested combo and get advice from one of the tech's. You'll be much happier if you do.

paulmoore

Well, when I spoke with the rep from AFR, he told me that the 383/AFR 195cc combonation has been around for quite a while and is a tried and true application. I had even asked him about using the race/competition CNC job and he told me that there would be a tradeoff. Sure the head will flow more after the CNC port work, but port velocity will drop which results in my torque dropping off. Yeah, I'd pick up some more horsepower higher up, but I don't want to spin the engine that high to get it. He told me that if I decided to run it up there around 6500-6700 RPM, with the rest of the parts in my engine combo, that I have very good potential to make upwards of 540HP!! Quite impressive, but not for me. I'd rather let the engine live its life at a lower RPM. I'm also looking to keep some longevity out of this motor.

Then I called COMP cams about 40 minutes later, asking them about hydraulic roller cams/lifter/pushrods, etc. He told me that I could even go 1 step bigger on the camshaft, still make roughly the same amount of torque, but pick up about an extra 20HP. Once again, it would all come in at 6500+RPM. I'm just not willing to go that route.

5678TA

ok first off, the 230cc intake runners are way too big.. 230/236 duration is good for less than 200cc intake runners.. AFR 195 would be a good choice.. but if you are looking for torque, smaller is better.. but not too small.. about 180cc would give you tremendous low end torque.. but top end would be a little weaker.. i had ported and polished camelback heads on my 383.. it had a solid flat tappet cam with 248 duration.. very rough idle.. the heads i had were around 180cc and with a 650 cfm edelbrock, i could spin tires in second from 1500rpm up to redline.. i switched to 200cc brodix heads and an edelbrock 800cfm carb and now it pulls up top and boggs down low.. cant spin the tires like it used to.. but gained quite some power on top.. so if this is gonna be a street car, make sure you match your heads to your cam.. it will prevent problems like mine and give you a nice streetable motor with no hassles..

1983Fbody

I'm also gonna say 230cc is too big. I'm having a similar engine built 415ci w/ 215cc victor jr. heads and an rpm air gap intake and around 10.5:1 CR. You could always swap to a single plane and a larger cam later if you want to hit a magic hp level. I think you'll be more than satisfied with a broader tq band. That cam sounds good with 235ish duration and street-bound small blocks seem to like valve lift in the .550 range, anything more and you'll be trashing valvetrain in a couple of years.

edit- I don't plan on spinning past 5500rpm and there's always the bottle if you want more power out of a very streetable combo ;-)