[cadillac_al]

My truck has a mild 350 with Trick Flow heads, rv cam and Edelbrock 1409. It screams; and it's the first time I have been impressed with an Edelbrock carb. The 1409 comes jetted richer than the 1406. The 1409 has worked great on a couple other vehicles too. I have a new 1406 and it is a dog on every car I try it on; falls on it's face when I tromp on it. I plan to buy a calibration kit for it to richen it like my 1409 but in my experience these 1406's seem too lean. Yours was too rich on the dyno so maybe it is only the needle and seat leaking. I have never had luck with a Holley but I'm sure a dyno guy can set one up properly.

Mine also has a couple bent valves from a past over-rev I suspect. I can not get a smooth idle out of it and a vacuum gauge bounces like crazy. However it does run nice once it's going down the road and I can't feel that roughness at all at highway speeds or tromping on it. I don't think some leaking valves would cause your problem.

For peace of mind you probably should do a compression check and a vacuum check. Your timing specs sound close enough to me. In my experience too much timing advance will cause it to cough. You verified that when you tromp it the vacuum advance goes away and the engine should be happy enough with that 10 degrees of advance. It would be nice if you could try a carb off a good running engine to rule that out. I think I suspect the carb. Good luck