Differences in 302's between years?
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From: Waleska GA
Differences in 302's between years?
im about to get a 302, out of a 77 f-150, that was burning oil. I want to get a rebuild kit but it seems most kits i can find are for the older (up to 72) or newer(85-up) motors. What would the differences be in the block itself? any reason i cant use the kit for the older motors?
TIA
Ely
TIA
Ely
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From: Virginia
Differences in 302's between years?
The main difference is going to be the pistons. My book "How to rebuild your small block Ford" explains there are slight differences in the deck height and the compression height of the pistons. Also, the year 1977 is a transition year from older small chamber heads, to heads with a larger open chamber with the sled rocker arms. The pistons with the small chambered heads usually had a large cut-out in the piston to lower the compression. You will find alot of the 77 and later motors with flat top pistons, or pistons with a very slight dish, since the combustion chamber automatically lowers the compression ratio.
The later model 85-up engines use a different piston too. They used thinner rings, and some of the mustang motors (HO) were forged. But you can put the older style piston in an 85-up motor.
The later model 85-up engines use a different piston too. They used thinner rings, and some of the mustang motors (HO) were forged. But you can put the older style piston in an 85-up motor.
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From: Oklahoma
Differences in 302's between years?
I believe the change in the block deck height from 8.18" to 8.20" was in '70 with a corresponding change in piston height. Ford also went to a one-piece rear seal in the mid-80s. There was also a running change made to the intake manifold bolt pattern and water jacket opening shape done plus a switch to pedestal mount rockers (late 70's?). They changed the balance factor from 28.8 oz to 50 oz in '82.
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From: Virginia
Differences in 302's between years?
Of course you can't believe everything you read, but this is what the "how to rebuild..." book says.
deck height for 302(his diagram shows from the bottom of the rod to the top of the block with the piston at the top of the stroke)
1968-72 = 8.206 inches
1973-76 = 8.229 inches
1977-up = 8.206 inches
This blew me away when I first read it a couple of years ago, because I thought all 302's were the same. Why Ford did this, I don't know. I am guessing they must have wanted to lower compression, and instead of wasting gobs of heads and pistons(the normal way to lower compression) they had in stock at the factory, the just machined the block different.
deck height for 302(his diagram shows from the bottom of the rod to the top of the block with the piston at the top of the stroke)
1968-72 = 8.206 inches
1973-76 = 8.229 inches
1977-up = 8.206 inches
This blew me away when I first read it a couple of years ago, because I thought all 302's were the same. Why Ford did this, I don't know. I am guessing they must have wanted to lower compression, and instead of wasting gobs of heads and pistons(the normal way to lower compression) they had in stock at the factory, the just machined the block different.
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