oops there went the headgasket

[DrifterTom]

any ideas on a rb20det with stock bore. it seems that most of the available gskets are for more than stock bore. is more than 1.0mm bigger than bore size ok???thanks tom

[Carl H]

hg's come a hair larger than the bore to account for compression that it will undergo when you torque down the head.

[ehacker01]

A headgasket for an overbore should be fine. I've ran 350 headgaskets on 305s without problems (3.735" vs 4.0") so 1 mm shouldn't make a difference. I wouldn't run a stock size bore on an overbored motor though.