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Which 351 do I have?

3K views 11 replies 9 participants last post by  V8 BroncoII 
#1 ·
I have a 351 out of a late 60's Mustang, but I am not sure how to tell the difference between the three. Are there #'s on the block that would tell me which one I have? Any help would be appreciated.
Thanks,Bill
 
#2 ·
if your sure its a 351 then it can be one of 4. the windsor engine has small valve covers with rounded ends. the intake is very narrow next to the carb.

the clevland would have the bigger square covers with a wider intake and the T stat is out the front like the windsor.

351 M/ 400M look the same. the T stat is in the block in front of the intake and the bell housing is squared off on top.

and just on the off chance you found a boss it would have screwed in freeze plugs
 
G
#6 ·
If it is a C8 or C9 in the3 casting number it is a 68 or 69 block, the casting numbers are on the block just above the starter, If you have a Pent roof valve cover it is a Cleveland.

Post picts & decode the casting number.

Pull the valve cover to see if you have early 351w heads, they are the best, Look for a larger WF in the galley between the valves & Push rods, & 351 on the right side in the top of the head. Those are the small chamber 60cc with the large valves. The heads that came on the 4bbl Mach I's.
 
#10 ·
69s had everything 70 had... so it between 351 Cleveland or 351 Windsor. easy way to tell is the 351C is very large compareable sized to a Big Block so it would look stuffed. If its 351W it will be around the same size as a 289/302 since the 351Windsor heads can fit on the 289/302s :chauncy:
 
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