351m

351w or bust.

The 351M is good for trucks only. They don't have a huge aftermarket, but they're good for low end grunt. You'd be better off going with a Windsor or Cleveland.

The 351-400m motors only came with 2bbl carbs, and I believe edelbrock was the only aftermarket manufacturer to build a 4bbl manifold. Very little aftermarket parts available for these engines. The "m" stands for modified, but ford used the term very loosely. 351w heads must be modified (bolt holes, etc.) to use on the "m". It would be an expensive experiment.

351c and 351m are very closely related. the heads,oilpan, intake and periferals interchange. the major differences betwen them is the bellhousing and the main bearings pluss the 351m came out during the smog reduction era hence poor performance

rip the smog stuff off of an M engine, hook up the 351C-4v heads, edelbrock intake, and one of the cams that are out there for it, and you can actually have a pretty damn good engine. it's more of a torque engine than anything, owing to the fact that it's a truck engine...but...day-to-day, torque is more fun anyway. you can also find a 400 crank and instantly have a 400ci torque monster

I ran a 400m with 351m milled heads and an "rv" cam that I bought from p.a.w. in my street stock dirt car for 2yrs. Talk about torque. But I needed that torque to get off the turns, and it was a screamer. But on a 1/2 mile track I would float the valves by the end of the straightaway even with dual valve springs, a two barrel and stock manifold. This sucker was nothing but torque. Not an ideal street combo. This was with stock iron exhaust manifolds and an open Y-pipe. With a more radical cam (not allowed in my class), it would have had more top end, but it would have defeated my purpose. If I would have gone with the "w" motor, it would have been a lot less expensive, but what the hell, it was fun.

ashford said:

351c and 351m are very closely related. the heads,oilpan, intake and periferals interchange. the major differences betwen them is the bellhousing and the main bearings pluss the 351m came out during the smog reduction era hence poor performance

Click to expand...

The intakes do not interchange. The 351M/400 has a taller deck than the 351C and the 351C intake is too narrow without spacers. The heads also are not a direct changeover because the 351M/400 has smaller ports and neither are particulary suited to high rpm due to the long stroke and 3.00" mains. The 351M/400 have 385-series(429/460) bellhousing and engine mount patterns.

Why Ford redesigned the Trans-Am race inpired Cleveland into a heavy, low-revving, low powered truck engine is beyond me.

the redesign was so it could pass smog. nobody was making power back then, so it made a lot of sense to makea low-revving torque monster. it'd be a fun engine to have in a car if built right

makarov said:

I ran a 400m with 351m milled heads and an "rv" cam that I bought from p.a.w. in my street stock dirt car for 2yrs. Talk about torque. But I needed that torque to get off the turns, and it was a screamer. But on a 1/2 mile track I would float the valves by the end of the straightaway even with dual valve springs, a two barrel and stock manifold. This sucker was nothing but torque. Not an ideal street combo. This was with stock iron exhaust manifolds and an open Y-pipe. With a more radical cam (not allowed in my class), it would have had more top end, but it would have defeated my purpose. If I would have gone with the "w" motor, it would have been a lot less expensive, but what the hell, it was fun.

Click to expand...

Your not kidding about TQ in these 400's. My wife has a 78 F-150 4x4 with a 400,600 cfm edel 4bbl, edel dual plane int, tiny rv cam and just good dual ex w/balance tube (no headers) with turn downs on the muffler ends.

It's funny as hell to watch her fry up her 35" mud tires. she did it another time, but the tires hooked and snapped off the pin holding the rear leaf spring to the axle LOL. def a TQ monster. a great 4x4 motor

Scott

gonna need a tranny too

DreamStang said:

So putting this in a 67 coupe is or isn't a good idea while I rebuild the 390?

Click to expand...

well, that all depends on what your after overall. the beauty in the 400 is the TQ peaks very very low and makes an awesome stump puller, but their not a rev motor. their dead around 5k or so depending on the cam. My wife is a regular on the ford truck forums and it's surprizing the number of 4x4r's who prefer the 400 to the 460. granted the 460 can make a bunch more power and TQ, but it does so at a higher rpm, and most people want all their TQ from idle up to 3k.. My wifes 400 TQ peaks at just 2200 rpm. The 400 also has an almost perfect rod ratio.

Her original 351M went over 350k before the cam broke at an idle. thats not to bad in my book. Her 400 is an out of state truck, so there is no smog on it other than an EGR. she just had it smogged out here in calif with the 400 4bbl setup and it flew by smog and this was at a *test only* station

Hope this helps you decide
Scott