Inliners International Forums General Discussion Engines GM 4 cylinders 151 153 181

Your head is going to be right near 70CC. Why not use the 250 pistons and deck the block?
Check this out.

http://www.rbracing-rsr.com/compstaticcalc.html

I used
3.905 bore
3.6 stroke
.041 head gasket
10 CC dish
Zero deck
70CC head chamber

Get 9-1 compression. If the piston is only 6CC dish then slightly more compression. Tom