Using 351w Cyl Heads On A 302 Block

[Sewerrat]

I have a 74 Bronco with a 302 that needs upper head work. Someone suggested to me that the 302 head was not the best breather and said to find a set of 351w heads. Can anyone tell me if these head are a direct bolt on to the 302 and what type of intake can be used ? Will the cooling passages line up?

 

[BLADE262US]

Hello the answer is yes they will bolt right on because tha only difference in them is the size of the head bolt hole . 302 is 7/16 and 351W is 1/2 . The edelbrock aluminum heads you buy have 1/2 holes in them and when used on a 302 theres a special step washer that necks it down to 7/16 . The important part is the shape and size of the combustion chamber . If you take a set of heads off like an 1980 302 outta a truck and then outta a 1980 351w outta a truck and lay them side by side you will see no difference other than the headbolt hole size . The combustion chamber in these is very big and looks like a half circle not good for performance but good for emmisions . Now you take a set of heads from a 1986 5.0 HO which was geared more for performance then you will find it looks like a heart shape and is much tighter . The heart shape directs the fuel charge more toward the spark plug causeing much more efficient burn and a bit higher compression ratio . Sorry for not haveing the actual CC,s but im at work and dont have access to the info right now . Bolting these heads on any 302 or 351w ( have to drill the head bolt holes to 1/2 inch ) Will cause a very noticable increase in power and responce. Hope this helps if you want pics let me know cause I have a set of each of these heads in the garage right now . Also have a set of 19old heads from a 289 they have a very very tight combustion chamber with a hump in it. Guy I got it from said they were good for drag racing but wouldnt do too good off pump gas because of the high compression ratio .