Help with a 351M problem

Brandog209 · Sep 16, 2007

I got a 72 Fastback with a 351M. It's supposed to have a cleveland but someone must have done an engine swap before i bought the vehicle. Anyway I replaced the intake manifold & the carburetor but when it was time to put the distributor back in, it was giving me a hard time. To fix this problem i tried sticking a socket onto the oil pump shaft to rotate it & see if the distributor would fit onto it. But when i pulled the socket out, it pulled the shaft out with it. I then tried to drop it back in & it fell in somewhere and now i can't even see where it is. Do you guys think it would have fallen in to the oil pan? If that's the case i'll just take the oil pan off, but if not then i think i might be screwed on this one. Any help would be greatly appreciated.

D.Hearne · Sep 16, 2007

It's in the pan, time to remove the pan. While you're there, look at the crank casting numbers, maybe you'll be lucky and have a 400 in there instead of a POS 351M. What makes you think it is a 351M anyway ? To transplant one in there, someone would have had to fab custom motor mounts and swap the transmission to a big block C-6.

ratio411 · Sep 16, 2007

They are designed with a keeper that doesn't allow them to pull up or fall down.

The problem is that someone could have removed the keeper, or installed the shaft upside-down.
If so, it's time to pull the pan!
Sorry...

ratio411 · Sep 16, 2007

Whoops!
D beat me to it!

Hope you got a 400.
The 351m is a hermaphrodite at best.
You could always swap in a 400 crank and pistons...

Brandog209 · Sep 16, 2007

Well it should be an H code 351c 2v, but there is a sticker on the head cover that says its a 351m & it meets all emissions requirements for 1977. My car is a '72 though. I got a new intake for a 351m and it fit perfect. At first i was kind of bummed that it wasnt a cleveland, but one of my friends seems to think it came from a '77 Ford truck & if thats the case it should have more torque. Not sure if it came from a truck but it's definitely a 351m. Thanks for the advice, i will give it a shot this weekend.

ratio411 · Sep 16, 2007

Brandog209 said:
At first i was kind of bummed that it wasnt a cleveland, but one of my friends seems to think it came from a '77 Ford truck & if thats the case it should have more torque.

Couple points:
Cubic inches vs same cubic inches, I can't think of any 77 model engine that was better than earlier stuff. That year was the peak of mediocrity in the auto business.

Trucks didn't get the 351m to my knowledge.
A 77 PU would have a 400, while mid level FoMoCo cars like Torino and just about any Mercury would get a 351m.

Just because a given engine came in a truck, doesn't always give it more torque than a car engine. On occaision, the manufacturer makes significant changes to do this sort of thing, like long intake runners or different cams. However what Ford did was to use a different crankshaft. Instead of 3.5" stroke, they put a 4" stroke in that block to give the 351m more torque. The only problem is that it is called a 400 now...

D.Hearne · Sep 17, 2007

In this case same vs same isn't even close to being equal. The 351M was a dog. The heavier pistons limited it's rev potential. It may have had more torque, but that would only have been on the bottom end. Cams were retarded along with the ignition timing. Lots of 77 trucks had both the 351M and the 400. Only fix for a 351M is to stroke it back to a 400. Even then, that's only part of waking it up. You can do what I did with one and swap cams, I put a Summit RAcing p/n 5200 in one and it made a big difference, even being fed by the stock 2 bbl intake and a Holley 500 carb. It also had long tube headers. The 400's big drawback was the piston comp height, they only came to .100 of the deck. There is only one fix for that, get on the Ford Truck Enthusiest website and locate a company called TMI ent. He had a special run of 400 pistons made that fixed the comp height. Another good swap is a set of Aussie 2bbl Cleveland heads, these had the 4 bbl quench chambers with 2 bbl sized ports.

bnickel · Sep 17, 2007

the 351M came in every ford product from the torino on up to the trucks, i've even seen big heavy duty trucks (flatbeds, box trucks, etc.) with the 351m. i had one in my 74 ranchero and it was a total dog.

D, it could also have an FMX behind it rather than the c6. i've seen a few big body stangs that had 351m/400 engines in them that still had the original FMX that was behind the cleveland and the bellhousing from an early 351m/400 passenger car FMX. then you just need to find some 429 engine and frame mounts and you're good to go. i wouldn't do it myself but it can be done.

D.Hearne · Sep 17, 2007

I wasn't aware the FMX's had a bog block bell. The 429/406 mounts only fit those, the 351M/400 mounts are unique unto themselves, they don't fit anything else and nothing else fits them.

bnickel · Sep 17, 2007

D.Hearne said:
I wasn't aware the FMX's had a bog block bell. The 429/406 mounts only fit those, the 351M/400 mounts are unique unto themselves, they don't fit anything else and nothing else fits them.

yep, the FMX does have a bell for the 351m/400/429/460 and you're right about the engine mounts being unique to the 351m/400 but the frame mounts/stands for 71-73 429/460 will allow the 351m/400 to bolt into the mustang using the stock 351m/400 engine mounts

ratio411 · Sep 17, 2007

Not only did 351m come with FMX, they came with C4s on occaision.
That is where the BBF C4 bellhousings come from that folks use behind 460s.

D.Hearne · Sep 17, 2007

bnickel said:
yep, the FMX does have a bell for the 351m/400/429/460 and you're right about the engine mounts being unique to the 351m/400 but the frame mounts/stands for 71-73 429/460 will allow the 351m/400 to bolt into the mustang using the stock 351m/400 engine mounts

I see now, I forgot about the multi piece mounts in the Stangs.

stonecoldtx · Sep 18, 2007

Are you sure that it's really a 351M, and somebody didn't just replace the valve covers? The 351M uses the same basic heads as the 351C 2-V . . . and if this really is a 351C, somebody probably put a nice set of fancy valve covers on the engine, and wanted to keep them when he sold the car; with that being the case, he might have just gone out to a salvage yard and found a set of valve covers that would fit.

The best way to tell the difference between the 351C and the 351M/400, is to take a look at the top bolts on the bellhousing. If they're 4-5 inches or so apart, then it's a 351C; if they're around 8-10 inches apart, then it's a 351M/400--they use the same bellhousing bolt pattern as the 429/460 385-series engines.

stonecoldtx · Sep 18, 2007

ratio411 said:
" . . . Instead of 3.5" stroke, they put a 4" stroke in that block to give the 351m more torque. The only problem is that it is called a 400 now...

Well, that's PARTIALLY correct--actually, the 400 came out LONG before the 351M . . . I remember getting a '71 LTD in that had a broken crankshaft, and it was a 400.

If I recall correctly, the 351M came out in LATE '74 as a replacement for the 351C (the last year of production for that engine in the US); rumor has it what they did was take a 351W crank and placed it into the 400 block to get the 351M.

ratio411 · Sep 18, 2007

stonecoldtx said:
Well, that's PARTIALLY correct--actually, the 400 came out LONG before the 351M . . . I remember getting a '71 LTD in that had a broken crankshaft, and it was a 400.

If I recall correctly, the 351M came out in LATE '74 as a replacement for the 351C (the last year of production for that engine in the US); rumor has it what they did was take a 351W crank and placed it into the 400 block to get the 351M.

You are correct on all points.

The statement I made was just to illustrate how Ford gave the trucks more torque. Semi-fecious statement.
It's the truth though. When the 360 FE petered out in 76, Ford put the Modifieds in it's place. If you wanted a torquey truck, you got the 351m with a 4" stroke crank. Which we all know is the 400.
Point being is that they didn't bother with a 'truck cam' or any other tricks like that.
The comment was in response to a remark that a truck 351m was tricked out to be torquey-er than a car 351m. Wasn't the case.

D.Hearne · Sep 18, 2007

stonecoldtx said:
Well, that's PARTIALLY correct--actually, the 400 came out LONG before the 351M . . . I remember getting a '71 LTD in that had a broken crankshaft, and it was a 400.

If I recall correctly, the 351M came out in LATE '74 as a replacement for the 351C (the last year of production for that engine in the US); rumor has it what they did was take a 351W crank and placed it into the 400 block to get the 351M.

Actually you're partielly correct, the 351W crank isn't the same casting as the 351M. There's a shoulder on one, forward of the #1 main, that's not present on the other. It wasn't really a replacement for the Cleveland either. It was truly a "modified" engine intended to fill the production hole left by killing the Cleveland that the Windsor plant couldn't fill. They "modified" the 400 to make the 351M starting in the 75 model year.

ratio411 · Sep 18, 2007

Yeah, I didn't intend to support his statement that it was purely a 351w crank.
It's close enough though that I overlooked that point.

You're on the ball D...

Help with a 351M problem

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