351W heads on 302

[justinsane]

What does it take to use a set of 351 heads on a 302 block. I realize the 302 head bolts are 7/16 and the 351 1/2, any otherconcerns other than using spacers for the head bolts?

Thanks

 

[bmc69]

Unless you have a set of C9Os..you will probably be loosing compression relative to what you have now. Need more info on what 351W heads yr talking about putting in place of which year 302 heads.

 

[justinsane]

I realize combustion chamber size could differ, causing a compression loss, mostly wondering if there were any bolt up problems.

 

[SaddleUp]

You can either get sleeves for the bolts or there are also dimpled washers that can be used. Other than the difference in the bolts they will bolt right up.

 

[wildbill]

%) %) %) The old book has it you will lose 1 point of comp. with the W heads so run 10:1 and you will end up at 9:1 wich should work good good luck Bill %) ;D

 

[Slowpony]

Wildbills right, but that's assuming that your 302 is 10:1 now, or that your going to change the pistons to a 10:1 configuration.
I bought an engine that was 9:1 and the heads were shot. The Machine shop set me up with a nice set of heads from a mid-70's station wagon... which had a much larger camber size. BUT, when bolted to my mid-80's truck motor, the combination gave me something less than 8:1. I could advance the timing until it wouldn't run, but it would never ping.
Moral of the story, know what your getting yourself into. Find out the camber size you have, the size the 351w has and do the math.
Adapting the bolts is the easy apart. Which by the way, you should drill and tap the 302 for the 1/2" bolts. JMO

'Pony

 

[Bart]

Do yourself a favor and get a book from Peterson called "How to rebuild your Small block Ford". It has a lot of information in it on heads, combustion chambers and what combinations will give what c.r. There are some serious differences in heads.
Good luck.

 

[BoltBuster]

If your going to put all that money in the engine to make them work just go buy what will or the whole 351W and port them. Ford heads are a known flow problem, So before pouring money to make what works and loosing torque for HP seek out putting your money in Elderbrock or GT40 heads, Yea..... its a butt load of money but your going to dump that much or more to make what you have work and not end up with satisfaction of the torque.


(your going to need a cam, maybe a manifold,pushrods,rockerarms, heads rebuild or port and polish, cooling problems with water jacket line up)


Your not the only one who has thought of this do a google on it, I found loads with waht Ive pointed out above

 

[justinsane]

Thanks for the responses guys. I have the book on how to rebuild small block fords. On mine I'm doing the Edelbrock heads. This is for a friend who is building a nice 69 for his son. He can do without massive horsepower at 16.

Best Wishes,
Brian