69 351w 4v Heads....

[4XFLOORED]

What is the value of 1969 351w 4v heads ??
how well will the work on a 302 ? will my c/r be ok to sill run cal pump gas w/o pinging, will I be faced w/ any fitment isues?>>> thanks in advance

 

[BLADE262US]

There is a misconception that there is a difference between 351 w heads and 302 heads . The only real difference that there is between the two is the size of the bolts that hold it to the block . A 302 uses 7/16 head bolts and a 351w uses 1/2 inch head bolts . there are special shoulder bolts made by edelbrock and a few others that pop into the 1/2 hold and neck it down to 7/16 to bolt 351 heads directly to a 302 block . If you take 302 heads and drill the head bolt holes out to 1/2 inch they will bolt directly onto a 351w . Set one head from each of the same year side by side and you will not be able to tell a difference other than the size of the head bolt holes . Ive herd alot of people say well I bolted a set of 351W heads onto my 302 and it ran like a rapped ape well thats probably because you changed the heads for a reason and the ones you put on were in way better shape and the valves actually sealed up . There have been a few different combustion chamber shape changes over the years that yes I would agree will make a performance difference like putting a set of 1986 5.0 (302) HO ( high output ) heads on either a 302 or a 351 will produce some horsepower gains because of the shape and the better flow produced by this shape . If anyone has any doubts get a set of heads from each motor of the both year and break out the calipers and measure the valves pretty much bet ther identical. The thing about your 69 heads that are a downfall are that in 1969 we were all running leaded gas and the lead acted as a cushion for the valve to seat contact well since like 1974 or so we dont have lead in the gas anymore so if you were to put those heads back in service without haveing the machine work done to put hardened seats in them the valves would peen over in a short period of time and the motor would start running very badly . I think I have one of each of the different heads so I can provide pics of the different combustion chambers . I even have a set of 1966 289 heads that have a seriously small combustion chamber but again they have soft seats in them so there would be machine work cost but even those 289 heads will bolt directly to a 302 block and directly to a 351 block by drilling the head bolt holes out to 1/2 . Hope this info is helpful .

 

[Broncoholics]

Boy I could have used this info a few years ago.
Several years back I took off my 289 heads due to it running bad at idle, the valves were recessed up in the head about 1/4" due to no lead in the gas.
Had case hardened valve seats added and the motor ran like a million bucks!
But now I know I could have gone the cheap route and used my 351 heads.