[goodyear1984]

ur getting to scientific.6500 is fine for a 302.i mean up grading the cooling system come on dude i have a 347 with over 11.3 to 1 and mine is stock with electric fans doesnt go over 170.if ur engine isnt balanced good enough to 6500 u had a problem at day 1 when it was built u dont need to up grade bearing there only gonna go if theres a balance problem at this power level.if any thing get a good fluidine balancer or a pp balancer.there are so many people that do it to the stock bottom ends its not even funny.i ran 11.8 with a stock bottom end shifting at 6200 for 4 summers and 30,000 miles and now its in a carbed 85 still gettin the crap beat out of it. my friend has a 92 roller bottom end witha 150 shot shifts at 6500.its been done ive done it ive seen it..but that here nor there were talking about heads.bottom line if u can get a set of gt40 heads for a few hunderd and they dont need any work then get them any more than that get aluminum.its just stupid to put money in iron heads.they dissapate heat better via u can run more compression without detanation