86' Power Ram Q-jet to Holley?

[AP_Ben]

Hey guys I'm looking for someone to check my work. Got an 86' 3/4 ton 4x4. Had a stock Rochester Q-jet on a 360. All vaccum parts and emissions contraptions were removed by a "mechanic" before I bought it. It ran like holy crap. I already had a Holley 600cfm vaccum secondary new in box in the shop, so I installed it. I went through plugged all the vacuum leaks that weren't needed and hooked back up what I thought were the bare essentials (pb, timing advance, climate control, 4x4). The engine has a bad stumble under initial load(feels like a bad accel. pump). Here is what I have checked out so far new moroso 8.8 plug wires, msd coil, multiple accelerator pumps and power valves and accelerator pump timing, removed distributor and checked mechanical advance and vaccum advance, new plugs, checked and checked and checked engine timing. None of these things changed the stumble at all. The only things I have found that help are radically advancing the timing, or pulling the choke about half. So my next thought was mixture is just too lean. The carb has number 63 jets in it, but the plugs don't look like they're lean enough to cause it to run this bad. I drive it all the time and it just doesn't sound right even after you get past the initial gear shift and re-acceleration(sorry I forgot its 4-speed). I also put new flowmaster super 40 mufflers on it but not the tail pipes yet. Can any of you guys tell me what jet you're running if you've got a holley, or if there is a vaccum leak I might have missed or if the limited computer these have can change the timing because of a part not hooked up any more? I consider myself a decent mechanic but I'm about to come unscrewed with it, any ideas would be greatly appreciated, and I mean any ideas. LOL!!!

[712edf]

How many miles? Try a compression check, and a vacuum check. Maybe timing chain has stretched. I can imagine what a castrasted motor sounds like, I've had 'em.

[Minionsram]

Sounds like you have a gasket leak on your carb. I just went the other way on my 85 w350, had a Holley on it and put the q-jet back on it! Is the Holley that you just put on a square bore or spread bore? If it is a square bore did you use an adapter plate with it? Pull the carb back off and check to see if your gasket is torn or the wrong way. ( I have put the gasket on the wrong way on a spread bore before.)

A quick way to check the gasket for leaking is crank it and spray carb cleaner at the base of the carb ( or water) and if the engine changes then you have a leak on the gasket.