I am looking for a 390 to rebuild for my 73 F250. I found this on CL:
Ford 390 engine 1975

The seller provided the following by email:
It is a hour drive from where I am at, and I have never purchased an engine this way before. Would any of you take a gamble on this?

 

300$ aint bad even if the crank and rods are screwed. you can hone the block get a new forged crank and rods and if you are going to run the motor hard over 3000 rpm alot make sure to put holley jets #60-80 in your oil passages so you dont starve the bottom end for oil.

 

Is this '75 F250 a 4x4? if so, then the 390 came from elsewhere as Ford never put a 390 in a 4x4, not that it's a huge deal but i'd want to know the FE's true origins.

having said that be sure to check it's even a 390 and not a 360, they try to get passed off as such quite often.

360=3.50" stroke 390=3.78" stroke.

 

The first question that popped into my head is if this was really a 390 or not. But since I won't know until I drive up there, that is just going to be a wait-and-see type of thing. Since I also assume that this engine is completely assembled, I am mostly concerned with how big or a risk am I taking with this "running 390" if I get it home and it is not. If the block is shot, but the rods and crank are good, would I be able to recoup some of my $$?

 

I would definitley get some pics.Also see if he will take some of the # on the block and Im sure someone can confirm if it's a 390 or not.
I would also ask if he can meet you halfway.

 

Problem I see is that if it is not the original motor for the vehicle it's in, the block, crank, ect., may have been rebuilt and machined to its useable limits already.

 

If I needed one and the price was right I would go look at it. Doesn't mean you have to buy.
An hours drive is nothing if you have a need.

 

There is no number of any kind on any FE engine block that will determine the size of the engine.

All you will find are castings numbers, which are foundry marks and so are worthless, because they cannot be cross referenced to Ford part numbers.

Pics won't help either as all 1965/76 FE engines look identical.

1958/64's have an oil fill tube and rounded valve covers w/o any holes in them. 1965/76's have pent roofed shaped valve covers with holes in them for oil cap/smog valve.

1968/76 360/390's share the same block (and casting numbers!) as the bore is the same (4.05"). The only difference between the two is the stroke.

390 (3.78") has different crank, pistons, rods and rings than the 360 (3.50"). Everything else is the same.