Steve, thanks for the part number--- the number 10 is on the rear of my camshaft. Are there specific bearing mounts for this shaft or are they all the same within a range of years (for example '77--'83) ? My Haynes book shows the rear journals for this cam to be slightly larger than for all the other cams used.

Thanks everyone for the help. Niether the chain nor the cranshaft seem to be broken--just the bearing mounts (towers). Of course we won't know why they broke till the head is off. I'll probably have more questions then.

---G.W.