anybody ported pre cups?

[HANK1948]

I have my brothers 95 6.5 apart for a head gasket change, so I was wondering if anybody has ported a pre cup just the exit window radius the edges or something for better flow? just curious

[john8662]

I don't think so...

But, there is a better way, GM updated the precup design in the latest model turbo engines. They used the diamond precup, this cup has a little diamond logo on the precup face. The difference is that the opening coming out of the chamber is a lot wider.

[TurboDiverArt]

Originally posted by john8662:
I don't think so...

But, there is a better way, GM updated the precup design in the latest model turbo engines. They used the diamond precup, this cup has a little diamond logo on the precup face. The difference is that the opening coming out of the chamber is a lot wider. Didn't John Kennedy try different pre-cups and maybe even porting them? I think he came to the conclusion that bigger was not always better. I believe his conclusion was that the diamond pre-cup was the best one vs. going even bigger.

Maybe John can chime in if I got it wrong.

Art.