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351m questions

9K views 5 replies 6 participants last post by  mudpig83 
#1 ·
I have a 351m engine that I was wondering about building. I have read a lot on the 351m and the 351c engines a lot of parts are interchangable. But I was curious about the 351w engines. Are the exhaust manifolds different? Reason I am asking is because I will be putting the 351m into a '90 mustang and would rather just use 351w exhaust headers that i can get from a friend for a good price.
Any ideas on what to do with the 351m block? it was free so please dont say trash it - has 30,000miles on it, and i can build it up.

Are any parts itnerchangable from the 351m and 351w ? Anything interchangable from the 351c to the 351w ?

thanks
 
#3 ·
351m question

Hello,

I was in your same boat when I put a 351W in my 73 mach1 that had a 351C in it. the 351C and 351M share the same exhaust port flanges but the 351W uses the standard SBF exhaust port flanges(bolts are straight across on both sides of port, the 351C has staggered bolts ala BBC) also note the 351M has a BBF bolt pattern so you cannot swap transmissions over. If you have the trans from the 351M great, if not you have to find one that was on a 351M/400M/460/429.

Anything that fit on a 289/302/5.0/351W and 351C will work with the Windsor.
 
#5 ·
The 351M is part of the same 335 engine family as the 351C and 400 smallblocks. It is basically a destroked 400. The 400 is a Cleveland with taller deck heights, and replaced the old 390 FE in pickups because the FE couldn't meet emissions requirements in the 70s. Demand for a 5.7/5.8 liter engine remained strong, but the Windsor plant was already making all the 351s it could. With the 360 FE going out of production as well as the 351C, Ford dropped a crank with 1/2" shorter stroke into the tall 400 block to make the 351M so Ford could offer pickup & Bronco buyers roughly the same engine choices as Chevy & Dodge. It either has really long rods or tall pistons to make up the difference.

It's a 70's era smog motor that was never designed as a performance engine. But you can wake them up. Edelbrock and Cylinder Head Innovations (CHI) make performance heads that will bolt onto any 335 engine. Intake manifolds are few and far between. Edelbrock makes a performer dual plane intake, and Weiand makes an action plus dual plane. CHI makes a single plane. That's about it. Your situation with cams is better, as any cam that will work in a cleveland will work in the 351M, and any distributor that will fit a 335/385 series engine will work as well. 351C headers will bolt onto the engine, but the engine is wider due to the taller deck height so cleveland headers may not fit the application.

The good news is that a 400 crank will drop right in. The bad news is that this isn't going to be a cheap build up. Is it worth it? That's up to you.
 
#6 ·
351m build

I am building a 79 351m I have been reading up on them 351c heads and intake will bolt to the 351m but the intake needs a spacer but I am building one to what I am doing is changing the intake to a 4bbl and puting 202 intake and exhaust valve punched out 40 over with a 750 holly with 30 over jets justed for the top end I am looking about 1000.00 and the bottom end I have a 400 crank with a large towing cam for a 351c and litters with dish top pistons and a high vol oil pump and I have 1000.00 that's justed the bottom end I had to use the carb adater to put the 4bbl for now and that was like 90 buck from summit the heads are still the 2bbl heads when the top end is done adding a msd distributor with a med 6al box with a baster 2f coil when done hoping for about 600hp when I am done
 
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