I own a 66 F100 that was sitting for 2 years.
The original engine was 352 but I was told it was replaced about 69 with 390. All ID'S on engine still have 352 except the air cover that has 390 decal.
I have since replaced all hoses, plugs, fuel filter, fuel pump, water pump, etc.
The oil pan is dinged up abit and has moderate leakage.
I have very little experience with the inner workings of an engine but I beleive it is time for some major repairs. I would like to attempt most repairs myself.
I need some advice from all you experts on how to begin and what plan to put in place.
Should I purchase new engine or should I rebuild what I have?
There are only 63000 miles on odometer and the engine runs pretty good except for smoking. There is also quite alot of oil builup around spark plugs. I feel that a new engine replacement would probably be more fuel effecient,i.e. 352 or 360??
I really think I could do most of the work if I take my time.
Any way, all advice is greatly appreciated.
I look forward to your expert responses.
Thanks!

 

id just have it rebored 390 was great engines,from what little ive heard about the 352 and 360 i dont think theyll be a real difference in mpg,if you want decent mpg id get a 300

 

If you want to rebuild it, do the engine you have now. You'll know what you have when it's done. There aren't many engine rebuilders that would have a 390 in thier inventory. It was dropped by Ford in 1976. That was the last year in a truck. They did use an FE motor for 2 more years in the heavy truck line.

Barry

 

With 68k on the clock and given it's age, I'm thinking that the problem might well be confined to valve seals. Why undertake what you term a "major" repair when all that appears to be indicated is a fairly minor one? Although you say the engine runs well, to verify my Dx, just do a compression check. If the pressure in each cylinder is reasonably consistent (+/-20%), you're good enough to go. Alternatively, you could say "to heck with it" and just replace the seals and be good with going with the odds. If you've not done this job before, plan on spending an entire weekend day (not counting running for the valve spring compressor, the seals, and valve cover gaskets. Oh, you'll want some clothesline rope as well to stuff into the cylinder so the valve stem doesn't disappear into the cylinder when you remove the spring. While there are more details on replacing valve seals, my point is that it's not a very hard job...you've just got 16 valves to mess with, so why not relax, be unrushed and enjoy the experience/accomplishment a bit instead of doing it like you've got someone with a gun to your head?
Paul

 

i have a 352 myself and i would say if you have a 390 rebuild it!!!!! all fe blocks have 352 on the block, the best thing to do is measure bore and stroke to determine which fe motor you have, the 352 is a quick rpm builder with good top end, where the 390 is more torquey in the bottom but have heard gets better mpg than 352-360.

This should help-

http://www.mustangandfords.com/techarticles/15999/

 

If the block is intact, I always say rebuild it. Getting a rebuilt from a remanufacturer is a risk--I've seen mis-matched heads, pistons put in backwards, etc. Try pulling the heads and check for cylinder wear. If there's not much, take the heads in and have them rebuilt. Or you can replace the seals yourself. Whichever you decide, if you're happy with the engine you've got, repair it.

 

this is the only engine place i use and recommend www.rebuilt-auto-car-engines.com

 

Some great advise here, but take a look at the FE engine forum on this site and that will likely help answer alot of questions.