what could it be?

[raiden7800]

I am looking at purchasing an 81 1/2 ton with a 350 small block ,and 4speed (no granny gear). The guy doesnt know what is wrong with the engine, he said that it ran great, and one day he was coming home, and all the sudden it was chugging really badly, and would die, unless he held his foot on the pedal. No plooms of smoke, or weird noises, just wasnt running right. So he parked it, and 2 years later, I come along, and I want to get it running.

It sounds to me that the timing chain jumped, because now, it acts like it wants to start, but it cant. I tried for almost an hour to get it going and it just would not go, like it wasnt firing on more than 1 or 2 cylinders. It has spark to at least 1 plug, I checked a wire with the old screwdriver in the boot trick. It is an HEI system, with the stock Rock-chucker quarda-toilet.

Next time I go over, I am going to clean the plugs, and make sure they all get spark, and I am also going to check and make sure there are no obstructions in the exhaust. Ive heard stories about GM putting double layer exhaust pipes on some of the trucks where the pipes meet in the middle under the cab. And the inside layer comes apart and partially plugs the exhaust.

Any other ideas?