yeah, good point, you have a good carb, use it as a reference. the only important vacume issue is really the slide and diaghpram, and that thing can be pretty ragged and still idle. it just wont run at speed. when the pressure builds, the slide wont move, so it runs like crapola. it sounds like for some reason its not picking up gas, so its either a clogged jet issue, the idle screw is turned too far down, or the mixture screw is way off. or, the seal at the carb and intake is totally shot. but i think it'd have to be missing to not work that poorly. if you can spray gas in it, its not an iggnition probably. most likely. id say 99% not iggy. it sounds like youre going to right direction with it. keep working on it. you got the timing cam thing figured out and that could have had you stumped for a while.
later
jc