[DeadheadNM]

I've read the pump can seize over time and makes a racket but wouldn't suspect that would sound like an exhaust leak. If the diverter valve diaphragm fails it can produce a vacuum leak (read it can be cured by placing a BB in the signal hose to the valve) and continuously dump air into the exhaust manifolds that can cause back firing.

I found a guy who rebuilds divertor valves for the corvette crowd. Rock auto recently had a close out on some USA made reproduction diverter valves for like $10. These are plastic and the hose tubes oriented differently but I may use one until I can have the original unit rebuilt.

Next time Larry! Thanks for the pics!