FreeJay, hate to ask this, but are you CERTAIN that the engine you now have in the truck is a 390 ? What if you have a 360 ? Has the stroke ever been measured to be sure ? I have taken apart at least a half a dozen '390s' that were complained about as lacking power, and found them to be 360s. It is very possible that your engine was built by someone who didn't know the differance. All of the parts will fit, the bearings and rings and pin bushings and gaskets are all the same....but you end up with a low compression dog. It wouldn't cost anything to check, and you never know for sure until you check. DinosaurFan, on work's old cast off 'puter

 

Dino-It definately is a 390. The truck had a tired 360 when I bought it, I went to the pick n pull and did the stroke measurement and found a 390. I bought that 390 and had all the machining done, then my mechanic buddy assembled it. The build specs are in my gallery. But he's a chev guy so I'm not positive we ended up with all the right parts. It was a night and day difference over the 360 but I'm not sure it pulls any better than an average 350 chev. Maybe it was just out of tune somehow??

Ideally I'd like to find a real good FE guy around here to drive it and tune it for me.

 

If he was a "chevy guy" it's a good bet he used the stock pistons in it for a pickup truck 390 and you've got an 8 to 1 comp ratio. That would explain the missing power. If that's so, then you could stroke it to a 410 (3.98" stroke) and reuse the same pistons with no other change. Your only cost then would be the crank and flywheel.

 

Why change the flywheel?
Have the flywheel drilled for a external balanced motor or better yet have the crank internally balanced should you go to a 410 with a 428 crank.

 

As stated earlier in the thread the pistons are KB150s

 

Yea, that would work too, hadn't thought of that

 

Free, since it has to come apart to fix the oil into water leak, I would measure the stroke and make sure it was assembled with the correct parts. If the crank is okay, how about the timing chain ? The timing chain and gears recieved a built in retard in the early 70s. If you have one of those sets, the set intended for a late sixties car engine will run the cam straight up, and will help torque some. I would get rid of that cam, IMO it is majorly too small. One of my trucks has a 390 with the 343801 cam, a 750 holley on top of a CJ iron intake, and in front of a C6 with the stock convertor. This with 3.50 gears and 31 inch tall tires. It has no trouble pulling trailers. The '801 cam would do very well in your truck, I think. The stock intake is the next thing that has to go. You would do better with a sidewinder, an F427 or a Blue Thunder or a Performer RPM. You could also look at the boosters in your carb- most 600 holleys have a booster with a big bar in the middle. The boosters you want are annular discharge boosters, sometimes called 'ford truck boosters'. If you don't want to get a bigger carb, you can change the boosters in what you have now, but I think the 600 is too small. You will also need new springs to match the new cam. I wouldn't change the gears in your axles, turning the engine faster won't help with the tiny cam you have now. Are the vacuum and cetifugal advances working properly ? You'll also want to have an old pushrod handy, the reason you have oil leaking into the water is because lots of FEs develop a crack where there is an oil passage that goes from the cam up towards the heads. The shop will need a long drill to open up the passage so that they can press the pushrod ( with its ends cut off ) into the hole to act as a sleeve and fix your leak. If they look in their computer, there is an AERA bulletin about how to do it. DinosaurFan, on work's old cast off 'puter