I have the 351M in a 79 F-250 S/C Camper Special. It runs well, starts always. We have a 11' camper and the truck just carries it without a fault. What is all this about low oil pressure. The gauge is always just below the centre of normal. 172,000 kms. Maybe the guys who have no luck with these motors do not know what maintenance is!! No complaints other than the mileage. HA HA!!

 

My '78 F-250 HD has a 351M/C-6/Dana 61 combo w/ 191,000 miles going sort-of strong. I drive it to work (80-miles round trip) 2-3 days a week w/o a problem. My father-in-law bought it new just before my wife was born & sold it to me in 2000. I have a 400 & spare crank in the shop waiting on a rebuild.
Doc

 

I've got one in my 77 F150. I'm considering turning it into a 400 though but I'm not sure yet. It's been a good motor. Starts and runs good and has never had any work done to it other than oil changes and spark plugs.

 

78,
One of my trucks has a 351M. It is a 78 1/2 ton 2wd.
KingFisher

 

 

Got one in my 77 F150 4x4, it runs, that's about it. Oil pressure is 25 at high idle, 45 on the road, 12 when in gear.

Someone said "torque monster" ha ha. Had a mid 80's with a 302 that would run circles around this beast!

 

my 351m has 11,000 miles origional (whole truck has 11,000 miles)
love the motors, bought it with 5,400 miles, been working out the bugs
(exhaust leaks, carburator, alt, battery) all from sitting. got most of
the bugs worked out and runs strong. 1978 scs 351/c6/4.10 (dana 70)
just a little history, veh. was a fire truck for 25 years in ark. (benton)
drove to wash. from det. for scs bed bought off ebay. absolutely no rust
on veh. needs paint now. thanks ed

 

I have the 351M in my 79 F-150, it had low oil pressure and a little knock but it ran strong never left me anywhere I didn't want to be. Then the rod bearings spun and now it sits waiting to be rebuilt. I actually think I might just replace it with another 351M a guy has sitting around only has 2000 miles on it but it hasen't moved in ten years.

 

I own 3 Ford trucks with 351Ms. A 77 F100 stepside, a 78 F150 Lariet, and a 79 F100 shortbed. As far as I know the only one that has been rebuilt is the one in my 79. In my experience the 351M is a very good engine. I have not had any major problems with my trucks. My only complaint would be the bad gas mileage.

 

Believe it or not...my 351M (87k miles) idles so smooth that visually, you can't tell that it's even running...beats all I've ever seen. I wish the 289 in my wife's 68 Mustang coupe idled that smooth!

I know my 351M LOVES gas...I'm thinking seriously about a 460 crate motor swap! I figure the 460 can't do any worse on gas consumption...

Regards,
Scott

 

We have a 78 F-350 Camper Special w/351M in it. I think it has somewhere around 100K on it. Runs pretty good, starts up and idles decent. Oh by they way its for sale too

 

I have the 351m in my 78 250 ranger 4x4/np435/np205/dana44&60. I burn about 3/4 a quart of oil every 250 miles. I wont complain, because i have 128,000 miles on an original motor. I have only done regular maintenance on schedule. I hear a little ticking in the motor, but that could justbe the exhaust manifolds....i dont know. I will probably replace the timing chain with gears, and the water pump soon, just cause its probably about that time. I like to be safe then sorry. We are about to see how she does carrying a 12k lbs boat from san diego to lake havasu in a little while for memorial day weekend. Hey, you never know, I might be back here looking for help before you know it!!! As for the oil pressure probs... Dunno about that, I run 20-50 and always stay around mid- to hi mid range on the dash, she only runs a little low when the engine is hot, or in need of a change around 2500-3000 miles. She definetley idles rough, and sounds like a boat with her 3" single exhaust cat back...and as for torque monster, well, thats all she is good for. Used to get 15mpg, when I was at 77k, now at 128k, i get about 10...She might just need some adjustments. I LOVE THIS MOTOR!.

 

351m here too; 78 F250 supercab. 106000 miles I did put in a new timing chain in it. While I was in there I checked main bearings (they were still good) but I did find part of a cam bearing in my pan when cleaning out the pan. Guess thats why it' s always had lifters ticking away all the time. Hey after 20 years of ticking whats a little internal bleeding going to hurt?
But it idles smooth uses no oil and runs much better with the new staight up T-chain in it.

 

351M in my 79 F150 SC rebuilt it about 100k ago when it started knocking on start up. Crane rv cam helps power and mileage. What is a 351M but a Cleveland in disguise?

 

my 77 f250 4x4 has one and i just got it rebuilt. hopefully will last ne a good 10 years or so. what gears do i have by the way? 4.10 , 4.56 ? i dont know.