i have a 1980 F150 and it has a 351M engine in it. i was wondering if anyone could tell me how its different from the 351W. i thought the modified was a windsor and had 400 heads on it? or is it more like the cleveland?

 

A 351M is a 400, isn't it? I was thinking that it was a 351 block with 400 heads, or something like that. Come on, y'all. let us know!

 

a 351w ia a small block the biggest one, the 351m is a big block the smallest one, i think the 351m and the 400 use the same heads.

 

The 351M and 400 are an evolution of the 351 Cleveland. The 351M is a shorter stroke version of the 400.

The 351M/400 uses a taller deck block, the mains are bigger, and the bellhouse pattern is the same as the 385 series (429/460 engines).

The 351C and the 351M/400 can use the same cylinder head, obviously the 351C had high performance heads available in some configurations, where the 351M/400 were low compression.

http://www.wrljet.com/engines/cleveland.html has a nice write up of the 335 series engines.

 

Thanks, y'all, that's much better than what I had!