Looking at a 1994 Z28. It has some bolt ons. But, I think that the pistons are stock. My question is this...or are these....

1. Are stock 94 LT1 slugs cast aluminum?

2. What is the compression ratio of the stock pistons

2. What is a good choice for a performance replacement piston?

3. What sort of compression ratio should one shoot for? The aim is to have the highest compression, but still be able to use premium gasoline.

4. In reference to aftermarket/high performance pistons, what brand yield the greatest horsepower increase? I have tried to find figures on JE Forged pistons, but have failed to discover any dyno test results for comparisons betwixt stock pistons, and JE... in any configurations whatsoever, no less. Please, if you know the answer, share this modicum of knowledge with yours truly. I AM CURIOUS!!!!!! I have been told that JE pistons are not to replace stock pistons...and that they are for racing only. I do not know if I believe that is completely true- be that as it may, let us assume that we have a built 400 HP LT1 engine, using stock pistons. Then, we were to supplant the stock pistons with JE forged 11:1 pistons, 0.060 over. Assuming that is within the realm of possibility, what sort of power will the JE's add?


5. What all can be ported on an LT1 motor? Obviously the heads can. What about the exhaust manifolds? The intake? Anything else? What kind of results can we expect from all or one of those procedures?


Thanks Dudes- no bovine excrement, no monkey spank, and no computorially smacking me around like a red-headed step child.


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If the JE or whoever's pistons are of the same configuration as stock (flat-top, or dished, or domed, whatever it might be), then changing them will have absolutely no effect whatsoever on how much power the engine makes. Well, maybe a little; since racing pistons are lighter than stock ones, there will be less inertia-related loss from them than from stock ones. But, not a whole lot of difference, at best.

If you change the compression, then the power output may change. That has nothing to do with stock vs. high $$$$.

The reasons you buy more expensive pistons are: to get a configuration different from stock (more compression, less compression for a blower, or whatever); and above all, SURVIVAL. The pistons won't make more power, but they'll withstand more before they break.

 

stock compression in most cases is 10.4to1 I believe that the lt4 grand sport motors were 10.6to1. I am running impalla head gaskets on my motor they are .026 thick (thinner than stock) this with the heads being milled .010 gives me about 11to1 compression. The stock lt1 pistons are hypertech. stronger than cast but not as strong as forged. they are fine for most na applications, and mild nitrous. turbos and superchargers tend to easily lift ring lands. so if fi is in your future upgrade to a forged piston.
The heads and intake can be ported. get rid of the manifolds they suck. buy some headers.
hope this answers some of your questions.
Kory

 

pretty much everything he said but the LT4's used 3cc valve reliefs in there pistons instead of 4 in the LT1 and used 54.4 cc chambers rather then 58 in the LT1...that gave the LT4 10.8 over the LT1's 10.4...

due to the reverse cooling you can run A lot of timing and have it all in pretty early...mine is 37 degrees all in by 2,400...(2 light silver springs)....