I have a '78 F250 with 4 speed transmission. Am building my 351m into a 400. Clutch size is 11 inches on 351 and 12 inches on 400. Should I look for a flywheel to use on this application?


Thanks

 

I'd be real surprised if your 351M flywheel didn't already have the 12" drilling.
Alternatively, you could simply use a premium 11" clutch, or get a local clutch builder to make one for you with a bit higher capacity.

 

I know when I changed the motor in my 79 f-250 4x4 I had a 400 flywheel cut as I already had it off but ordered the 11" clutch and it wouldn't bolt up so I got the 12" and was told that both 11" and 12" should.When I finally pulled my old flywheel it to only had one set of bolt holes for the 11" clutch also and was told it should have two sets hmm.