If you don't have a 4 barrel intake, keep you eyes out for one as they often go pretty cheap at swap meets or on craig's list etc. They have good torque, but aren't particularly high revving, but that should be fine in an F250.

 

The best thing about the 351M/400 engines is that it has the same mount locations as a 302/351W.

This was posted on a different Ford forum when the top of the 400 came up.

 

That photo. That photo -- it's beautiful.

 

Looking at the back of the intake, I would guess that engine is a small block chebbie. Maybe a 351m or 400 wouldn't rust that bad as an anchor.

 

Nope that is a 351M/400 block. It has canted valves and the BBF bellhousing bolt pattern. Chevy intakes have paired runners where Fords are separated.
Look at this picture for comparison: (The right one. Left is a 351C)

The camshaft plug and oil galley plugs are a dead giveaway.

 

Husker, I found an "Offenhauser" aluminum intake at a swap meet and mounted a rebuilt "Demon" 4-barrel on it. I've only had it running once for a very short time. I'm in process doing a lot of body work right now. I need to re-wire the whole system as well, so I've got lots of work yet to do...

 

I have one in my 1980 4x4. I got it from a friend of mine who got it from the previous owner when it stopped running. They had just put new bushing in it, new plugs, wires, cap, etc. Couldn't get it to run again. I found out a part sheared in the oil pump, locked it up, then it broke the distributor gear in half. New oil pump, new non retarded timing, timing chain and it was good to go.

It has 30" tires on it and 3.50 gears, spins them over fine in 4x4 at a dead stop. I got a 4v intake for it but haven't gotten the 500 CFM EDL manual choke carb I want for it yet. Later on I want to drop a small cam into it and a set of headers. It still has the stock exhaust on it for now.

For a everyday v-8 I am happy with it, it is just a bump around truck.

 

Wow thanks for all the insite about the motor.
Thanks
Dan