I have searched this site and others to find the answer to this question to no avail. I would like to swap an externally balanced 460 in place of a 400. I have a T-18 with a cast iron bellhousing in it now, (1979 F250 4x4) and would like to know what the answer is before I spend $150 on a flywheel I can't return. I have heard that the answer for internally balanced engines is to use a 390 flywheel and a 400 clutch, but I haven't seen anything on the externally balanced 460. Anyone know the answer?

 

I'm not sure the question is clear. Use a 460 flywheel and clutch for or from a newer truck.

 

The question is: does an externally balanced flywheel fit in the 351M/400 bellhousing? Has anyone actually checked to see if the parts fit? If it doesn't, do I have to buy the flywheel from L and L or is there another option?

 

The later counter balanced 460 manual flywheels take the same starter ring as the 400's so the outside dia. has to be the same. If you can pick up a used one from a late 80's/early 90's 460 you should be good to go.
Richard