Max, my 77 F250/4x4/351M/NP435, lost oil pressure, clickity clacking lifters and running rough, wasn't the best runner to start with,,,
I bought a 76 with the 300 I6/NP435 I was going to pull and then junk the rest, it's rusted and rough, I also have a 351C, and a 302, both ready to run, and another 300 I6 that I need to rebuild.
I'm at a point where I need to decide which one goes where,,,
I have Mater, my 63 F250/4x4/Custom Cab/Factory Platform bed,,, I pulled the 292 out and sold it like an idiot,, got the 351C to put in it, but have considered the 300, will only be a play around, light wheeling truck.
My 77 250 previously mentioned,, now needs a heart transplant, it is the worker, wood cutting, off-roading/wheeling exploring/hunting truck, I had a 79 F250/4x4 with the 300 and it was a great truck, got 18mpg driving it to MO for my BIL, was considering the 300 for my 77.
My 78 Bronco/NP435 has the 351Measly also, haven't done anything with it, hoping Kalifornia will change smog rules soon,,maybe
and last but not least, shrek, my 66 F100,,, has the 240 I6/T18,, he's due for a rebuild, smokes a bit while coasting and some while driving, but he still runs, thought about bumping him up to the 300 I need to rebuild.
So 3 good running engines, 1 truck that needs it now, and so on and so forth,,, any opinions, ideas, input is greatly appreciated.
Thanks
Joe

 

I'd probably go with the 300 over the 302. Don't use the 240 without putting a 300 rotating assembly in the bottom.

I think/suspect/assume that these trucks are harder on, and will cause more wear on, a 302 than they are/will on a 300. 300s were never put in cars by Ford.
But the supply of 302s and the sheer amount of go-fast stuff available for them is a good argument in that direction too. A late '90s GT40 spec Explorer 5.0 would probably be a pretty good engine for that application with some aftermarket valve springs and maybe an RV cam.

 

Yeah, the 302 I bought for my 66 for when I rebuild the 240, or if get another truck,,, LOL, I need another like a hole in the head, but,,, ya never know
I was debating the 351C or the 300 for my 63, but now that my 77 needs one, I'm leaning towards the 300 for it,, but I've never had a 351C in anything,,, not sure if I'd like it more in my 63 or 77, all are 4 speeds and will stay that way, even my 78 Bronco is a 4 speed, main reason I bought it.

 

Personally id go with the 300 given the options. Not as racy as a 302 but itll actually work like a truck and 300s last forever.

Personally if it were me id rebuild the 351M with a 400 rotating assembly, straight up timing gear, and the other usual stuff.

The 300 used to be my favorite ford truck engine, till i owned a couple 400s.

 

Join me on the dark side! I can make your engine and transmission mounts for really cheap. Gen V chevy engines have direct injection, come with 6 speed automatics, better power mileage etc

Attachment 281225

 

Dont do some EFI swap please, it has already ruined enough of these trucks. I would build the 300. Get a 4 barrel intake, camshaft, EFI split exhaust manifolds, and if you really want, you can do a 240 head too. The 300 is by far my favorite engine ever built.

 

Well, just on cubic inches, I'd put the biggest engine in the truck that needs it the most. IF the 351C is ready to run, then run it. It's not like you haven't swapped an engine before. There's no way a 300 makes as much torque as a 351.

The 240 was put in a passenger car, our old County Judge owned one. My friend had a '65 F350 with the 240 and 4-speed, Dana 70 rear. I pulled a 5,000lb Mercedes S class with trailer for over 450 miles and got nearly 16mpg. I really liked that engine. I'd think twice before turning it into a 300.

IF you have the money and the time, using the 351M block with a 4" crank and Tim Meyer's pistons plus whatever else Tim has or recommends will get you the most power with very good economy. Pretty much everything except the pistons and crank of the 351M can be used in the 400.

Choices, choices................
R.

 

The 300 is by far my favorite also the last 3 I've had I had offy intake, heddman headers and Holley 390 4bbl, the olny issue I have putting the 300 in place of the 351Measly is sourcing the engine perches to go from V8 to I6, not sure if the 351C is a direct bolt in, with correct BH of course. I'm not sure which truck the 351C would be better in, my 77 F250 has 4.10's/33's, my 63 F250 has 4.56's/33's

 

I've got a 240 in my '77 F150 with a 3.03 three speed and a 9 inch with 2.75:1 or so gears, and it will slow down on hills on the highway. The torque is good, but the gap between 2nd and 3rd gear is too much for the powerband of this engine - this is noticeable at about 45MPH on an uphill grade, trying to maintain speed. If I have to lift the pedal off of the floor for traffic or whatever, the truck will just keep decelerating until I downshift to 2nd. The carburetor isn't very good, so that could be the problem.
I will almost certainly stay with the big six in my rig, but I'll procure those extra 60 cubes at the first good opportunity...

 

Gearing is everything, my 66 F100 wT18/240 "Shrek", had 3.00's in the rear when I got him, couldn't pull a hill to save his life, I bought the 302 thinking the 240 was just too tired, started having a noise in the drivetrain, rplc'd u-joints, pulled 9" and went,, oooh,,, found a 9" with 3.70's, WHOLE different truck, I have 265/70/15's, now he runs likes a champ, smokes a bit, but is fun to drive, put the rpm's in the strong spot, AND my mileage increased, now I can run down the hill to fresburg and get 16-18mpg.
I'm leaning towards the 300 in my 77 more so, he has NP435 and 4.10's w/33's, same as my 79 I sold to my BIL and Woody got 18mpg driving from CA to MO, with a 4bbl. Right now my 77 "Max" gets maybe 8, and that's when he was running good. Choices, choices,,,,

 

 

If the truck is not going to see a lot of heavy hauling on road or lots of hyway use the 300 would be the most economical and provide decent milage. Other wise i would opt for the 351C providing you can transplant it with the regs in your area. The swap will be similar to dropping in the 302. Same motor mounts and bell housing as the 302. It won't take much work to wake up the 351C and it will make more torque at all RPM's than the 300 will and you have the advantage that it will rev higher than the 300 or 351M is needed.

Converting the 351M to a 400 is a viable option also as that literally just an engine rebuild using a 400 crank. A cam upgrade bump in compression and a 4BBL intake and carb can turn the 400's in to torque monsters that will rev decently.

 

460 and done (yeah I know its not on the option list). Far more aftermarket support and parts. I've driven a 351m and a 300 and my 460 is far funner to drive short of the 410 Merc what was replaced by the 300 to sell the truck. I wouldn't put a 302 or a 351c in a 3/4 ton truck. The 351c is basically a short deck 351m.

Second place is 351m to 400 rebuild.

But, you need to know your DEQ laws before doing anything.

 

Even though they share the same displacement they are nothing alike even stock form.

 

Are you sure your not confusing that with the 351W? Cleveland, 351m/400 are the 335 family of engines and share/interchange some parts.