75 XL Cam shims

Fist off thanks Chuck on the bushing info. I really thought that was whatr I was going to have to do all along. Secondly, if anyone is familiar with the cam shims on an iron head, I have a question. When I pulled the case off I found there were no shims period. Its been years since I had one apart and I was wondering what problems would this create other than noise. Also I found that the worm gear on the crank that drives the oil pump breather gear was in backward. The reason I am asking is the engine has a nasty noise in the lower rear which starts about 30 seconds after start up. Like a gear bounching into another. I thought it was the starter gear drifting out into the ring gear but not so. So I then went into the cam case looking for something amiss in there but all gears look fine. My next choice is something floating around in the tranny. Any ideas appreciated. Thanks Russ

75 XL nightmare

Well when I stated the oil pump gear was in backward, I meant the worm gear thats on the crank. There is a mark on it that is supposed to face outward but was facing inward instead. Its all in time now. However it looks like the lifter blocks need to be yanked to check cam end play and thats where I have to quit becuase I dont have the "special tool" needed. I also found one of the pins for a brass bushing in the case is missing. That could make a noise like I was hearing if it was floating around in the oil and bouncing off the cam gears. However there is no evidence of it anywhere. No marks on the cam teeth or parts of it in the oil or in the cam cavity. Plus I dont see how its possible for it to come out once the outer end of the cam is in the bushing anyway. Its 20 degrees out and the ground is snow covered so my enthusiasm is is lacking. I may just button it up and send it down the road. Russ