I put a noisy Pete Jackson in my 65' Fleetside, and to be quite honest it's not that loud. Sounds more like a power steering pump going bad. I'm suspecting that it's not installed with the proper clearances even though I did everything step-by-step per instructions. I even did the clearance check between the idler and the timing cover with clay. Any ideas as to why mine isn't that loud?
I also didn't know about the listed "negatives" about gear drives transferring harmonics and vibrations to the valve train. Makes perfectly good sense now that I think about it. Only bad thing I've ever heard is the idler gears coming appart.