Originally Posted by HeyYou

I have almost 200K miles on mine, so, I am quite sure the valve seals are shot. I have my doubts about the valve guides as well, not to mention piston rings..... I haven't really done much diagnosis on it, mainly because even if I find what's wrong, I can't afford to fix it. I have another motor hanging on the engine stand in the garage, the plan, hopefully, is to 'freshen' it up this spring, and install it......

Originally Posted by Ham Bone

Well im about to slap some heads on my truck as I still have great compression on the 240k engine in a last ditch effort to avoid a full on rebuild until i get out of college. No smoke after it burns off the intial stuff. No significant blow by that i can tell.

Wish me luck I know its probably bad to put new heads on an old block.. oh well at teh very least i dont have to buy heads again.

Originally Posted by Snowfan

The 'new heads on old block' theory generally does not apply to Magnum blocks because they are super high in nickel. Thats what my engine guy says.

I have 5000+ miles on my new heads and it runs excellent.