so I broke in the new motor this weekend, buddy of mine and myself were breaking in the cam . 2000 rpm for 3 ten minute cycles. about the end of the second ten minutes, the motor popped out the exhaust, then gradually decreased in idle then finally croaked. it was ticking right off nice up to that. I am breaking it in pretty rich..could it be loading up , popping , then fouling? any help is greatly appreciated, as a new motor that won't run more than 10 minutes is disheartening. all the valves are lashed correctly, and I find it very hard to believe I hurt the cam. any ideas gentleman? ( the 280 magnum cam sounds sweet b.t.w)oh yeah. I also have a rebuilt hei dist. with a correctly converted engine harness.

oh yeah.. the valves remained lashed.. weren't ticking (indicating a flat lobe)and all the plugs are consistently black

It's possible they're fouled, but it's an easy check - pull them, clean them, and start it up again. I only hesitate to say that if something else might be wrong, but it seems you've got your bases covered. Maybe check your oil before you start it up, look for metal particles just in case.

yeah thats what I figure. I am going to drain it tonight, but I would assume I should find some fine particles shouldn't I? from the cam establishing a wear pattern right? It really sounds strong, and I am itching to get this thing tuned perfectly, car itself still needs a bit of work, but now my musclecar has muscle.. smile.gif