I'm wondering if anyone's ever had a problem with a holley high vol fuel pump arm interfering with the timing chain? At first I thought maybe the double-row timing chain was the culprit, but then I tried this pump in a stock original motor, and it still interferes big-time! I took the pump back to the parts store, and best we can tell, Holley may have put the wrong pump in the box The box says on it plainly "429-460", they also ordered in another pump earlier this week and it is the same way.
When you set one of these pumps side-by-side with a stock pump, or my old Mr. Gasket pump, the Holley lacks a "dog-leg" for chain clearance.