my 66 olds 425cid wont stay in time. i have a fairly oversized crane cam in it with the original distibutor setup (points/condenser) i used to get it up and running good at 10 degrees advanced. the problem is that when i get it dialed in and the distributor clamp tight and drive around the block the timing goes off again. any suggestions...maybe my points are shot?

Has the cam been worn in? Is this a fresh rebuild by any chance?

the rebuild was done a bout 20k ago. so the cam is worn in. its wierd its like the distributor turns itself out of time after the a few minutes. i had this problem in the past and usually after spending awhile and re-timing it it will settle in and be ok, but this year its being a real pain.

Perhaps the distributor gear drive is all worn out, enough play in the gears will throw the timing out after so many thousand revolutions, maybe?

It's just an idea, I'm probably wrong.

very possible...it is an old stock distributor. i never replaced the gear. i will have to check it out...thanks