Now now guys, lets not be too hard on the Ms. Lord knows Ive cussed em myself, but lets face it, they just go and go and go. They're nothin special, but I still wouldnt trade my 351 for any Chevy 350! The 400 has the longest stroke of any Ford motor ever made (I think?) so in theory, one should be able to build a real torque monster. Besides, we know the 460 can be built to run like heck, the Ms are a challange. One problem is, they dont have the aftermarket support of the 385 series which means building a 351/400 is limited unless you spend big $ for custom parts. Remember, we are talking about a Ford motor, and Ford has never built a BAD motor (except for maybe that v6 truck motor in the early 80s). Technically, my 351M truck will outrun my 95 F350 with a 460 FI, but the 460 will outpull the 351 truck any day. Oh well, enough of that.

Nathan

 

If you're going to put it together as a near stock motor or if you enjoy the challenge of scrounging and improvising (and have the money to spend) then by all means build up the M.

If you're going to get serious about performance and cost is an issue, then you can get a whole lot more engine for a whole lot less effort and money starting with the 460. Either way you'll have a killer torque monster.

Longest stroke?? The 400 just edges the 410/428 and 300 I-6 by 4.00 inches to 3.98 but all three trail the 5.4 V-8 and the 6.8 V-10 at 4.165"

 

Interesting opinions. I do appreciate everyone's thoughts on which engine is best. For my application though, I didn't want to "goober" my completely original F150 4wd truck complete w/factory tilt and cruise with a different engine than that it came with. That goes to say that a big block switch was not even considered.

And as for the new 351W, sure you'll get plenty of new ideas talking to a Ford parts guy but I'm just fine with the technology the truck came with.

I did like the idea of adding just a few more cubes with the 400 to get more torque. The truck is more show than go right now and sees little use. If I can get to it, I'm calling to order my performance remanuf. 400 today. Thanks for the input.

 

the 351M/400 are 335 series motors. its the cleveland not the windsor motor that is most interchangeable. the only major difference in the 351 & 400 M is the pistons & crank. the 400 having been developed first and the 351 created by shortening the stroke and modifying the piston. for comparason the 71 400M had flat topped pistons and developed a respectable 9.0:1 with the right modifications, its possible to get an estimated 325+ horse out of it. i have asmassed a ton of stuff while trying to learn about my 79 bronco. i will gladly share with and who email me.
AXAVIERE@AOL.COM


several FAQ's are given here for you to refer to...
https://www.ford-trucks.com/articles/mblock.html
http://www.projectbronco.com/History/history_of_the_ford_351m.htm