251 spifire

[244ENBN]

As fate would have it a 251 complete clutch transmission and P.T.O. were given to me ! I know Canadian M37s came with 251's. How hard would it be to stuff it in an American 1951 M37? I took rough measurements and it seems workable pretty easily. Also how much more HP is a 251 vs 230? Will a 24V distributor fit a 251 block? The 230 in my M37 is toast so I'm just trying to figure out if swapping in this 251 is a better choice than rebuilding my 230, if its going to be a big deal I'll just keep the 230.

[MSeriesRebuild]

As fate would have it a 251 complete clutch transmission and P.T.O. were given to me ! I know Canadian M37s came with 251's. How hard would it be to stuff it in an American 1951 M37? I took rough measurements and it seems workable pretty easily. Also how much more HP is a 251 vs 230? Will a 24V distributor fit a 251 block? The 230 in my M37 is toast so I'm just trying to figure out if swapping in this 251 is a better choice than rebuilding my 230, if its going to be a big deal I'll just keep the 230.

The 251 is 2" longer, moving the front engine mount points up onto the cross member instead of at the angle brackets will solve that issue. The radiator core must move forward 1.25" to accomodate the extra length. This is accomplished by repositioning the mounting brackets on each side of the radiator frame in such a way that the core is shifted forward. This covers the basic will-fit issues. The distributor from a 230 is not interchangeable with a 251. The 251 shaft is approx .25" longer. The distributor housing & other internals are the same so changing out the shaft to the longer 251 shaft solves that problem. If you are certain the 251 you have is top notch, go for it, if not I would be sure before going to the trouble. A compression test on the 251 will answer that question for you quickly, run a test before proceeding. If you need further advice after the test, post the test results here, will be happy to help.

[244ENBN]

Charles Thanks for the info. As always very helpful. The more I think about it the more tempting this swap is to me.

[MSeriesRebuild]

Charles Thanks for the info. As always very helpful. The more I think about it the more tempting this swap is to me.

I failed to mention checking the 251 for a cracked block, this is common in both the 230 & 251. You deinitely want to be sure the block is good before proceeding.