I posted it on his fb page. Thanks man, hes a stubborn sob so we shall see lol
CK5
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Buddies buildin a 383
- Thread starter Deuling
- Start date
He is waiting on tbi from CFM technologies or something, then its break in time 
I convinced him red would look nice
I convinced him red would look nice
with 64cc head and 12cc dished pistons 9.8:1 compression
Flat tops would be insane if you intend to run pump gas. I would say that with those Iron heads it's also going to be to high with dished pistons.
I have a very similiar build and you can even search and find mine.
I'm running a 54mm TBI with eldelbrok etec 200 heads and a lunati 60120 roller cam.
The motor is a beast and spins 35" tires with ease.
Brian at tbichips is good at tuning those motors. But I'm going to call it and say your going to have detonation problems with that motor. Going to lose major power potential by having to retard the timing a bunch.
From the eagle kit
Kit #B13404E (2pc seal) B13404L (1pc seal) Eagle SBC 383 Stroker Rotating Assembly, Cast/Steel EXTERNAL Balance Eagle 3.75 Stroke Crank, Eagle 5.7" Bushed SIR Rods, Speed Pro Hypereutectic Pistons .030, .040, .060 pistons, 9.8:1 comp w/64 cc heads, 9:1 with 72 cc heads, Speed Pro Moly Rings & Clevite Bearings.These kit only come balanced.
Another thing to watch out for because I have been there done that. That kit probably came with a 153 tooth flexplate. Your starter will not work and you will need to get a different one.
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You saying the engine itself will have problems or the tbi?
And this is not for my truck, its a buddies motor for his rig, 91 GMC Sierra 2500 new body style.
And this is not for my truck, its a buddies motor for his rig, 91 GMC Sierra 2500 new body style.
I'm saying that motor with those iron tbi heads will have problems with 9.8:1 compression ratio. Will detonate on premium. I have "vortec" heads which are better with detonation and mine are aluminum which is supposed to be even better and I can get mine to detonate on premium. Mine has reasonable timing I cant imagine what crappy iron tbi heads will do.
If he wants to keep iron tbi heads I'd search for a set of 76cc heads will run a lot better.
Im pretty sure he got the pistons seperately, Keith Blacks I beleive.
What's important is how much they are dished. I think those eagle kits come with KB pistons also if you order them that way. Not much different other then the name. I'd do him a favor and call eagle and find out what he has. That motor will go boom in short order if he has 9.8:1 compression.
So its just a bad setup for the heads he is running is what your saying? Or is it just a bad setup in general?
What he is getting at is with that piston/head combination the engine will have too much compression to run on pump gas with out retarding the timing. If you have to retard the timing to get it to run without pre-ignition problems it will run crappy. And thats retarded
You either need a different head or different pistons to lower compression.
You either need a different head or different pistons to lower compression.
Why go tbi unless he wants to be off camber a bunch. Would have been cheaper to go with a nice carb, and way easier to tune. TBI and performance do not got hand and hand.
I dont know I think you can still get some decent power out of a TBI.
I'm gonna guess mine is in the 350hp and 400 some odd pounds of torque with a 54mm TBI. Carbs are easier but some of us have to pass smog tests.
Yes exactlyWhat he is getting at is with that piston/head combination the engine will have too much compression to run on pump gas with out retarding the timing. If you have to retard the timing to get it to run without pre-ignition problems it will run crappy. And thats retarded
You either need a different head or different pistons to lower compression.
It had tbi, he wants to keep it that way, i beleive this tbi is all set up for his motor its a custom built tbi unit i guess. On the heads i guess we will have to see how it runs, couldnt he put higher octane gas in to make up for it?
Highest pump gas is premium unless you go buy race gas which is really expensive. Some people say put octane booster in, yes octane booster helps some it will raise the octane 1 or 2 points. Don't believe what you read on those octane bottles pure marketing BS. IMO octane booster is a poor substitute for real octane. I've had my fair share of high compression engines and they never run good on octane booster IMO.
But to answer your question higher grade fuel is an expensive fix but yes that will work.
As far as custom built TBI yes that is what I have from the same place your buddy got his I have the 54mm version. But in order for it to work he will still need to retune his ECM. Also what fuel injectors did he get with that TBI? I'm running 61lb injectors at 22psi
Its a toy, if it runs like h3ll he can get by with expencive gas for a while untill he gets heads. Hes not going to mess around with it right now, we are planning on break in sunday. Let me see what he has on the actual specs of the motor before stuff gets assumed.
He also said he got the 9.7:1 kit, idk if its that much different, just throwing it out there.
It may be more of an issue in that truck Adam, but you've seen how my Vette runs with Iron 64cc heads and these flatops (4 valve relief),
Those pistons are on their 2nd build...forged TRW's
I believe the figured static compression to be about 10.0:1, w/ a .038 gasket, it runs fine on 93, but when I race it I run race gas.
Those pistons are on their 2nd build...forged TRW's
I believe the figured static compression to be about 10.0:1, w/ a .038 gasket, it runs fine on 93, but when I race it I run race gas.
3MAX
1/2 ton status
I just built a 383 using Eagle's kit with flat tops (5cc in the valve reliefs I believe). Also running 64cc vortec heads. I had my machine shop check everything - actual combustion chamber volume measured 65cc, and they set me up with thicker than normal head gaskets (0.050 I think) to bring compression down to 10.2:1. This is about as high as you want to go on premium gas. Not sure exactly what size his chambers are, or what gasket he's running, but he's going to be very close to needing race fuel for that motor...
couple things I notice you have manual fuel pump so probably running carburetor. do you know what thermostat is in that? 180? TBI runs 195 more prone to detonation. Also which heads do you have TBI heads suck donkey balls.
I know a lightweight car (2900) makes a big diff too, the heads are the 2.02/1.60 camelback's ported, and bowl work done, milled .010 too. I run a 180 thermo and a carb.
Vortec heads are NOT the same as TBI heads. Vortec heads can support higher compression without detonation. Although I dont think I would have used flat tops with 64cc heads either
Could be depending on where you are your premium is actually higher then other areas. Where I am at premium is 93 octane.
