Hey everyone, I have a 1986 F-250 with the original 460. It was a work truck for a number of years until a very small under
hood fire when it was parked next to a barn for 8 years. When I bought it, it barely ran. Since then my father and I have tried
our best to get it running. The only thing engine-wise that we have bought is a Holley 3310-2 750 CFM carb. It still runs poorly.
It blows some serious black smoke when you mat it, also. It was running good until slowing down on the road when it would
stall. We adjusted some things on the carb and now it runs like crap. Tonight we tested the compression (not sure how
accurately because we have never done it before), and every cylinder rose fast to 135-140 except one. This one is #7 I believe.
It's the second from the firewall on the drivers side. That
rose slowly and only to about 90 the first time. After we sprayed some oil in the hole like it said to, it rose to about 120. I think
that is related to my next problem... The valve cover breather tube/oil filler is blowing out as much exhaust smoke as a Honda.
My father thinks it's got something to do with a plugged exhaust port or piston ring. Next: I have another 460 block in the
basement (D9TE-AB) that I plan on boring out and building up nicely over time, but I was wondering if my current motor was
worth fixing up. The parts I am planning on replacing on this motor are: Rear main seal, piston rings, intake manifold
(edelbrock performer), Valves and valve guides, cam, thermostat housing, pre '71 timing chain, recurved distributor, electric fan,
main bearings, clutch, dipstick tube, throwout bearing(if it has one), pressure plate(if it has one), and a new air cleaner. Does that sound like it would
fix any problems I might have and be reliable for a couple years? Thanks, Austynn.

P.S. Please add anything else you think I should add to the list.

 

Oh, I forgot to mention, please suggest part numbers or names for lots of torque. I already have headers, but I'll probably need to get rebuilt heads as well.

 

I'm getting dizzy reading all that

Lets pick this apart a little at a time.

Mosy likely the floats go stuck in the carb it happnes. BTW the factory used 600 "650" cfm carbs on these engines. 750 isnt too big but a 600 would better suite the factory cam and timing curve.

#7 is nearly dead oil rasing the compression would indicate the rings are worn. It's possible the cyl got washed out when the carb started acting up. Check the oil for gas.

I'd suggest you guys turn the idle mixture screws in all the way then back them out 2 full turns for a base setting then check the float level. After you get it running for a while recheck the compression on that hole.

Building another engine would be ok, Just get an engine kit and get a cam that suites your needs.

 

compression doesn't sound bad for an old work truck. Except for #7. I'd pull valve cover on that side and make sure rockers are working. Could be a stuck valve or partially stuck valve.
As for exhaust pouring out of oil, fill/breather. Change PCV. Sitting for 8 yrs. the old one probably don't work anymore.

 

Thanks for the advice. I already replaced the PCV valve about 100 miles ago.

 

Hi. Among your long post I see listed the edlebrock performer manifold. I use this on my 86 250 and have found no problems other than with the carb the hood just makes locking into place. I also have headers with flowmaster. Neighbors complained of the loudness so I put in some Magnaflow resonators. So far so good. Good luck with your engine.