[Walt Fricke]

From memory, the early chain boxes on the sand cast cases did not have as many studs to hold the covers on, which means you can't just use the later covers. The later covers have 10 studs on one side, and 11 on the other. The later covers also have, on the left side, two longer 8mm studs - part of smog pumps and whatnot. But it is easy just to use long 6mm studs and nice washers if that is the only issue.

If you use the late style idler arm, and the last, 930 part number, tensioner used just before the pressure tensioners, you should have no problems anyway. And you can attach a collar to the tensioner which will limit how far it can collapse, in the unlikely event it does collapse.

Just so you have options. Bruce Anderson's book shows an early cover with a sort of bung welded and milled to accept the pressure fed tensioner.