Went to tune up my F100 for the first time today (bought her just two months ago and have been pretty busy). Quickly discovered that the #8 plug was badly fouled. Ran a compression test (warm engine) and the numbers were 150, 155, 150, 145, 170, 75, 160, and 70. If I remember correctly, 175-185 would be normal, so I have some loss in 1-4 and major problems in 6 and 8. A shot of gear oil brought #1 from 150 to 170, and #6 from 75 to 135. Looks like rings to me, and definitely time to do a bottom end rebuild (and stroke to 390, of course).

Also, it occurs to me that I won't be using anything from my current motor save the block and heads. A stroker rebuild will require new crank and rods, and I'll of course replace the pistons. I'm also adding a new intake manifold and headers, and a new carb. Of course I'll replace the timing set, oil pump, water pump, etc. Given all that, would I be better off just buying a decent rebuildable 390 core rather than trying to stroke my 390? A big advantage, of course, is I could keep my truck running with the existing 360 until the 390 is completed and ready to drop in. Any ideas what a decent price on a rebuildable 390 would be? And are there particular years and variations I should look for or avoid?

Thanks

Any other suggestions/advice?

ksd
69 F100 Explorer lwb 2wd FE 360 C6. WANTED: straight/clean styleside long box w/aux fuel tank for 67-69 F series.

 

I live within a couple miles of a junkyard that gets 40 bucks for any V8 shortblock and 70 for a complete engine. Try and find a big pull it yourself yard. You definitely have problems with your 360. Bet it runs about the same or better than mine. There are no particular castings to stay away from but a 74-76 motor with a mirror image 105 on the block instead of 352 has thicker cylinder walls and reinforced mains. Don't forget the oiling mods.

 

70 bucks for a complete engine? Where would that be? It might be worth the trip if they have a couple of 390s to choose from.

ksd
69 F100 Explorer lwb 2wd FE 360 C6. WANTED: straight/clean styleside long box w/aux fuel tank for 67-69 F series.

 

I would just add that if you run across a D4TE block, (casting number below the alternator) look over it real close. They have a tendency for cracks or fractures around and in-between the freeze plugs, especially on the passenger side. You will be able to tell by the staining and rust marks. Look also on the bellhousing side of the block too.

Barry

 

I live in Oklahoma City and the junk yard I'm talking about is called Pull-A-Part. They have at least 6 360/390 blocks out there. Not sure about there condition.