I am putting together a 455 bored .40. ( 4.165.) I am installing a silvolite cast piston .40 10:1 how do i figure the ring gap? hasting steel molly rings 2m 661 040

thanks

 

No info on the box the pistons came in? If not, call the piston company, and ask what they recommend.

 

The old rule of thumb is “.003-004 per inch of bore”.

4.165x .004= .016666. Obviously, if the ring or piston manufacturer specified something different if use their recommendation.

 

thanks for the info

 

K,
Those rings are standard gap rings and should be fine just the way they are as long as the bore is exactly .040" oversize or slightly bigger. Silvolite cast pistons do not require any type of unusual gaps.