max bore on a 86-88 302 ho engine

stang · 02-18-2007

looking for max bore. if bored over 0.30 in what would be some good heads to go with combo. maybe gt 40

FoxChassis · 02-18-2007

WHY do you want/need to overbore? You should only overbore to clean up the cylinders, i.e. high ridges, scratches, scores, etc.

There is only ONE reason to go with a huge overbore, and that is to clear oversized valves/reduce shrouding. And factory production blocks shouldn't go any larger than a .030" overbore anyway. Cylinder walls are already thin and factoring 'core shift' into the equation is only asking for trouble.

NOSty Pony · 02-18-2007

30 over makes for a nice 306 and GT40 heads would work great.

830hp · 02-19-2007

i have gone as large as .060. no need to go this far.if cleans up .010 you well get more rebuilds on it.

stang · 02-20-2007

any spec sheets. is 306 just bored 30 over. what is compression ratio with 306. is power gain noticable between 302 and 306

830hp · 02-20-2007

their is no hp diff between 302 or 306 if built the same.go to 331 or 347 for change in hp.if some one tells you diff they have there butts in head.i have building engines for 18yrs.from 250hp-1900hptwin turbos. dyno over 1500 engines in my shop.