decompressing styles

[pwrstrokenstang]

what are the pros and cons of decompressing by dishing out the bowl, meaning cutting out the cone vs just opening up the bowl. also will a decompressed engine turn higher r's easier?

 

[LReiff]

I think it depends some on the motor, some on the piston bowl design and some on what's needed for valve clearance. Stock LB7 duramax pistons have a lip around the top outside rim of the bowl that some choose to remove. If you're working on a cummins, cutting valve reliefs to fit a high lift cam drops compression.