I have a 383 LT1 (3.750 stroke)with 6" rods and -16cc dished pistons that are .30 over...I have a 68cc head and it is built for low compression...I want to tear it apart and put the compression up around 11/12:1...Basicly i want to get rid of my supercharger and run nitrous occasionally. What things should i look for in a piston like compression height and cc's? domed or flat top? And what are the views on Hyper pistons or should i just go for forged? Any help will be greatly appreciated..

 

CH is solely a function of the stroke, rod length, block deck height, and desired piston to deck distance. To get your desired CR you are going to need a small dome or to have the heads milled. A -5cc flat top will only put you at ~10.6:1 with zero deck. Most people will say that the flat top/small chamber makes more power. That's true, but you could argue how much with just a small dome. OTOH, you may find it hard to get on off-the-shelf piston fitting your needs - you need a dome in the 5cc range. So, that leaves milling and flat tops as the best bet, IMHO.

People use HE pistons with nitrous, but I wouldn't. I am old, and old fashioned.

Rich

 

I would not use hyper pistons on a nitrous platform. While it may work for awhile, they really were not designed for the major increase in heat.\

 

Thanks Rich, I was hoping you would see the post..lol...my block deck height is 9.010. So I should look for a flat top and have my heads milled a little. Is there any specefic Flat top i should look for besides one for a 6" rod?

 

Yes thats what i've heard. I ran a 100 shot on the stock bottom end for 2 summers....Are the hyper pistons better than the stock pistons or not so good?

 

In a stock replacement scenario, I have seen good results.

 

So they may not be good in a stroker???with a little 100-150 shot??? Guess i'll be looking for forged ones...lol

 

Flat tops come in many "flavors". You want to avoid the "light weight" versions and pick one specifically designated for "small nitrous" use. This involves the thickness of the crown, the location of the top ring (how far down from the crown) and the wrist pin. Lightweight wristpins should be avoided. You do not need a piston designated for large amounts of N2O - they are sturdier but unnecessarily heavy.

Rich