Hey Guys!! I just bought a 73 F250 for it's STRONG 390. It hadn't hadn't run in 5 years, and ran really raggedy and smoked big time. By the time it had run an hour or so, however, it had smoothed out nicely, and had quit smoking. I pulled the plugs(which didn't look too bad) and checked the compression. It was very consistant--though low. It ranged from 80 to 90 dry, and from 85 to 95 wet.
I'd really like to hear your opinions on whether I should take a chance, and install this in my 66, or, should I go ahead and re-ring it. I've got a long, boring winter ahead of me here in Idaho, so, Iv'e got the time to do it.
I respect you guy's opinions and would sure like to hear from you!
Thanks,
Brett

 

Brett, Did you measure the stroke yet? Very likely the engine is a 360, 390s were available special order but the 360 was standard.

I think you might be happy with the engine like it is, they'll make the sap rise in you. Pull the engine, degrease it, paint it, an run it for a while. The compression is fairly even across the board, and I have been told that is good.

If ya got the funds for the parts, and the skill, you will be happy with a fresh 390 next spring no doubt. arg arg arg

PS: Ya gotta have a blue tip close at hand to remove the exhaust manifold bolts. I don't give a hoot how much PB Blaster you squirt them with for how long, them puppies are stuck tight. Ya gotta make very small right and left hand turns to get then loose and out. Get the manifold cherry all the way around the bolt.

John

 

Well puting a re-ring kit in will definitely eat up the long winter, as well as a dry out your back pocket... Because you had said she smoothed out after running for a while, I'd have to side with JW on this one. Pull it out, clean it up, run some Marvel mystery oil through it, maybe change out the valve stem seals, rebuild the carb and run till she drops. I would also check to make sure you ahave the 390 you expect, if not, you can save some money and plan for the 390 build up when it's ready for real work.

Just my $.02's, --Mike

 

Thanks Guys!! I'll have to check to find out if it's a 360 or 390. Your advice to run it til it drops suits me just fine--parts are spendy!

 

Well biggut, I've fond on the 360 engines that I have had in the past that they have had some raised embosments along the sides of the block, around the soft plugs, that the other FE engines do not have. That's the way I've check for a 360, but do not know if this is 100% true. Also the 390s I have had had chanfered cranks and the 352-360's have been square cut throws. Also not 100% sure of this, but has worked out that way for me each time. When you ran this engine, that had not run in 5 years, did you put in new fuel and oil?

 

Allen, You may not be very far off. The easiest method of checking for a 390 is measuring the stroke from a spark plug hole. The standard FE engine was the 352 and replacement 360. With my CRS I disremember the first year for the 360. The 360 is a 390 bore block with a 352 crank. There were a few 390s installed in pickups but I'm guessing 1% or less.

Somehow they all become 390s on day of sale because you can't look at them and tell any difference. I'll confess that I have nodded yes when asked if my truck has a 390. (don't let that out, and blow my cover)

John

 

The 360 replaced the 352 in the 1968 production run.

FWIW, --Mike