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from my brief mic-ing of the pistons. we're looking at 1+mm dome increase on the silvertop over the hi-comp. here's your quick compression bump by merely fitting a 16v head atop a complete silvertop 20v bottom end for a 1620 setup EVEN with a factory head gasket.

oh nice. you should have known i was going to ask but....

what is the piston compression height for the silver top and is it the same as the high comp?

the compression gains of the ST over the hi-comp (latter w/ coated pistons) is .2! with the TRD .8 or .5mm gasket you get to closer to the 11+ compression. or milled with factory gasket but you lose more chamber area.

i figured there was a small difference in comp higth between the 20v and the 16v. thanks occa

what about the change in combustion chamber volume? and what do you mean by the "high comp"

sorry for digging up an old thread

no worries.

i was just comparing the ST pistons to the smallport/hi-comp pistons as per toyota's published compression numbers per motor models.

so when you say "hi comp" you mean a smallport?

correct. one strange setup i have come across recently is a 7 rib bottom end large port sporting low comp pistons but with a 20mm wrist. check it out:



notice any differences?

got a picture of the top of those?