Well, you confused enough yet????

 

It maybe technically a big block, but it was designed to be a cheaper motor then the 460. It will bolt-in where a 460 is and use most of the accesories, and the tranny too. Thus saving Ford money since there is no swapping before the swap.

It is a Tall Deck 351C with 99% of the time a 460 tans bolt pattern. It shares many of the same faults the the 351C has, but now a days is a viable contendor on the street.

Since the 400 has a long stroke I would use a torque came with a touch of duration something like a Comp 268 cam or smaller.

 

What needs changed (besides tranny bellhousing) to drop a 302 or 351w in the engine bay inplace of a 351m-400? I have a 302,c6 and np205 set-up im pondering of putting in one of my trucks, what motor mounts would i need?

 

The 351 M &400 both have big block bolt patterns on bell housing and motor mounts, they also have a 1" taller deck.
So the Cleveland IS a Small Block, while the other two are Big Blocks. Not that it matters in this context, but the crank mains are smaller on the Cleveland as well.
The 351 Cleveland was the most powerful small block ever built by a factory! Bar none.

 

Nearly 14 years later.....awakened from the dead.

 

Well... in 14 years I hope we've learned the 351M and 400 aren't "big blocks", but rather tall deck small blocks!

 

Just adding to this old thread .....

Any engine that will loose most all of it's oil pressure near Chatsworth Ga. while passing a milk tanker on old US-411, then go on down to Carrolton over next to Alabama, then back over to Hampton, Ga. (was Richard's last race, Bill won the race, but Alan held the lead long enough to get those 5 extra points and win the championship), then back to Carrolton, then bring me home, with a Shop Smith MK-V and all accessories, us, & our luggage, across the mountains of north Ga. and up through BlueRidge, Ga. and Murphy, NC. into western NC. including the Smokies and work back to Bristol, Tn./Va. & then up I-81 at 63-65 mph steady to arrive 200 more miles deep into Va at near midnight (total miles since notice oil pressure loss was easily 7-800) --> AND then live another 30 plus years with just new bearings rolled in and a new stock spec oil pump-- and to this day that will maintain 60-70 psi hot at 2500 rpm ... is A-OK by me.

It got a lumpity-lump Crane Fireball cam in late '80s, with only new lifters. I'm sure some flat top pistons would be more-better for power, but OEM is some easy on the starter if that helps. It had already gotten an intake, carb, ignition perks too before that 1992 trip.

I really thought was a bad sending unit that trip, swapped in two on the road, then thought maybe just a bad gauge as it just ran on & on. Got home, checked it with a real gauge, it had 4 psi. Bearings were worn into the copper at under 75,000 miles. I'm almost glad I didn't "know" for if I had I would have not continued on. I only had the electric OEM gauge then, but ever since then I use a mechanical "real" gauge.

I could have shortened that trip, but I really only heard that lifter rattle once when passing that tractor trailer on US-411 near Chatsworth, Ga. I guess that 400 on the stand since early in 1993 has been good insurance. It was a gift then, I reworked the short block ... (machine work, hot tank, bearings, rings and 8 new pistons, etc) ... done then as a back up plan, and it hangs on an engine stand to this day. I did not then expect the 351M to just "BE THE BUNNY" and keep going like it has. I even added a little bracing to my engine stand so it wouldn't tire of holding the 400 aloft so long. I'm figuring as long as the 351M serves, the 400 can sleep.

Wednesday 12-18-2024 I took it in for safety inspection, it passed, has 108,500 odd miles now. I did roll in new bearings again last year just looking around to see how it looked in there, turns out it was pretty much OK.

I had also put "Slick 50" in the oil the previous change, some said it was why it got home, others said it was the cause of the issue? I only ever used it that one time so I don't know.

..... just to say ......... that the 351M was de-stroked from the 400 that got a tall deck for that 4" stroke, after it was derived from the 351C. 351Ms and 400s have Cleveland heads, the intake is wider because the taller block moves them further apart. 351M as well as the 400 is a "small block" technically, but it is a "large" small block.