short story...
i have a 78 F150 reg cab long bed4x4, its stock height with a 32" tall BFG all terrains. I use the truck to drive to work when itsnows and rains and i use it to go hunting with. NO OFFROADING OR MUDDING
About a year and a half ago the motor went, cam was so shot it seized to the cam bearings and spun the front two. So i brought the motor to a motor builder and he told me about 800 dollars to check the crank and bearings, check the pistons, check the heads and fix the cam bearings. Then i stil need to buy a new cam and whatever other parts ill need.
SO i now have two choices either spend a grand and have my motor rebuilt (which i dont want to do) or buy another motor
motor #1- rebuilt straight six from a 79 F150, has under 6 thousandmiles but i need different motormounts, flex plate etc to make it fit my truck
motor #2and#3 - running 351M thats bored but the owner doesnt know by how much for $250 or a running 400M bored 30 over that has under 50k on it for $300

For what im doing im looking at the 400M only because the 351M even though is running doesnt have enough info for the bore and mileage. So what would yous do in my situation

 

From the options listed I would also go with the 400. Sounds like you have an automatic trans? If so then you need a new transmission to get the 300 in there. Don't forget about the ever popular 460 swap, it will bolt to your existing transmission.

 

$800 just to "check" the engine and replace cam bearings? .. PLUS whatever else he allegedly finds. I find that insulting. Gee whiz.. I wonder what he will find [sarcasm intended]. That sounds like a teaser to extort more and more money and hold your engine hostage.

I'd go with the 400. That way the engine architecture, accessories, trans, etc. stays the same and thus reduces the overall cost. Open it up and check the main and rod bearings. If OK, then freshen it up with a full engine gasket kit after replacing the timing chain and oil pump. At 50K miles, it is beyond is half-life and makes sense to do in my opinion.

 

I think the 400 is the best option too. A lot of people think they are dogs, that's because they are in stock form. As mentioned, just freshen'r up a bit. A new intake and carb would help wake'r up too.

 

Hell for $300, I'd go with the 400. I've seen 400s last forever. In fact, when I got my 77 out of some trees for a restore there was what appeared to be a crappy 400 in it with no intake or carb and dirty. I took it out and replaced it with a stroker. My brother who is a mechanic was just going to throw the motor out, but decided to keep it. Down the road a customer that didn't have much money and a beater of a 77 supercab needed a motor so my brother checked the 400 over, threw a used intake and carb on it, changed the oil and the dang thing fired right up and to this day is still running. That was 6 years ago.

 

I'd go with the rebuilt 400 but more importantly you have the best avitar ever! Uncle SI rules. Lol

 

yea I'm gonna buy the 400, over the past year Ive been buying new parts for my 351M but since everything fits the 400 this is what im gonna install in it.

New oil pump and pickup tube, new timing chain set, new cam (4x4 cam), new valve seal and valve springs, new head gaskets, other seals, new harmonic balancer

i also have a Edelbrock non egr aluminum intake and their matching 600cfm carb for it also. Like i said i don't want a 400hp mud bog motor just something thats gonna start, drive me to work, take me hunting, haul wood for the winter so i can burn it out in the garage

 

I recommend a set of headers to take full advantage of the increased displacement, cam, intake, and carb combination.

Vroom.

 

im going to not right away since i have a brand new y-pipe on the truck and im not happy about trashing it. But i will change it after a while

 

It sounds like the 400 it is. I pulled out my tired 351m and dropped a 400 in my truck. You need to check the specs on the cam lift, you'll probably have to change the valve springs too.

 

probally going to buy a Edelbrock kit, but i have no idea what one to get? Summit has like twenty listed and i dont know whats what....

 

heres the cam's I'm looking at

Lunati Voodoo Cam and Lifter Kits 10320702LK - SummitRacing.com

Edelbrock Performer-Plus Cam and Lifter Kits 2172 - SummitRacing.com

i looked at Comp but none of their cams make power from middle up, only around 1500rpmand up. Not what I'm looking for in a 4x4