Swapping to a 351
 

Well, I have been having F.I. probs with my 95 5.0. I kicked around the idea of carbing the thing, but then I decided otherwise. I have a 1978 ford bronco with a 351 M in it. I think this might be the answer to my prob. I am going to doa little swap, reducing my bronco to a 5 liter. What do you guys think about a 351 M. Also, where can I look for performance goodies like heads for the thing? Anyone done a swap similar to this that can give me advice?? Would appreciate input, thanx ahead of time.:D

I am not positive but I think the 351m has about no aftermarket suport at all. Even the 351c has limited aftermarket parts, but there 4v heads are kick *** and I don't THINK they will fit on a 351m. The 351m's came in trucks and that is what they are good for not a mustang.
Wade

I agree. THe 351M I believe is a Marine application, someone correct me if I'm wrong. Either way, you need to find a Winsdor if you want to save many headaches.

351 M is for Modified 400 , cross between clevland and big block.


heavy and hard to find performace parts find a 351 W 71-74 block 69-70 have diffrent deck heights and are a little diffrent but stong if you get a complete one. heads block crank ect.

Don't waste your time with a 351M (the M doesn't stand for anything). Any cleveland head will fit it and some other c parts. You can put on the 4V C heads but you have to run a 4V C intake and spacers (the M and 400 have a more than 1" taller deck height than the C) and you will have to have custom made headers. The cam and timing chain and gears and cover and oil pan will all interchange between the M and C. Rods, pistons, crank and push rods are all different. Also, your bronco (78) will have the crappy smog 2V heads. These are basically the same as a 2V C head but it has a big bump in the exhaust port. Also the flywheel and clutch from the stang won't work (the 351M uses 28.x oz balance). And the M motor mounts are 351M and 400 only bastards. The bellhousing pattern is the same as the 429/460 so your tranny won't even bolt up.

The 351M/400 is great for a 4x4 cause it has good low end torque and not much else. They are part of the 335 series engine family which started with the 351C in '70 (400 in '71, 351M in '75 to replace the 351C which ended in '74). The 429/460's are the 385 series. Really Ford never called them Big Blocks and Small Blocks back at that time. The 335 series and 385 series will interchange distributers and rocker arms.

You would be looking at way more work than gain with that swap.

351M/400 = 351 modified 400

No it doesn't. Per Ford the M has no meaning other than to tell the three 351's apart. Although I do admit that I call them Modifieds as well.