I am about to tear into the engine and replace the pistions. I belive I broke a ring land, because of high crankcase pressure and rough running.

I have researched JE pistons (Extreme Duty inverted dome) #131636 that are forged and has a -22cc dish. Even with that dish, my LT4 heads (54.4 cc) will be putting out close to 10.0:1 CR. I can have custom pistons made to about -33cc, that will bring my CR to about 9.0, assuming deck height and head gaskets are normal. If I go that route, there are a lot of additional variables, such as ring gaps, and types of rings. I am considering 6.00" rods, but I understand they rob from low end and give to high end.

I am all ears to suggestions and experience.

I have an ATI 8# SC and want this to be a daily cruise missile, not an Atlas booster rocket.

Joe

 

HOw much boost are you looking at pushing?? Are you going with a stroker or just boring it over .030? Ideally you want anywhere from 9-9.5:1 compression. For my setup I went with -31cc JE pistons, and 5.875 OLiver Rods. I had my heads hogged out to 58cc. This gave me a compression around 9:1. Personally I would go with either JE pistons or SRP

 

What cam are you running? What really counts is dynamic CR, not static CR.

Rich Krause

 

I replaced my pistons with TRW's Speed PRO Blower/Turbo pistons and to get the CR where I needed the builder removed material from the walls of the dish in the piston, (made the dish bigger). This may be an option for you also?