Agreed, I think there's a decent vacuum leak somewhere, just gotta track it down.
Agreed, I think there's a decent vacuum leak somewhere, just gotta track it down.
Also, pop the distributor cap and make sure the advance weights aren't seized.
I think the combination of issues it has means it probably has fuel AND ignition issues. Not that you don't need a choke, but that's not what's causing these issues, nor is the accelerator pump (although that doesn't mean it's working!). Most likely the stalling issue is running out of fuel. If you have a spray fuel like starting fluid or brake cleaner you could verify that pretty easily by just spraying at it as it stumbles and seeing if it picks back up. I think you are outrunning your fuel supply due to weak pump or a restriction. The long crank time after stalling also correlates with this (filling up the empty float bowl). As far as the rpm change, try unplugging your vacuum advance hose to the distributor and see if it still happens. I can imagine a situation where the throttle stop and idle mixture screw settings are so screwed up that the engine runs so poorly when it first starts that it doesn't make much intake vacuum, and as it settles into a little stronger idle and makes some vacuum, the throttle plate being cranked open too far sends ported vacuum to the distributor which adds 20* of timing and makes rpm go to 3000 until the fuel dries up.
I think as a 'baseline' i would set the throttle stops and idle mixture screws to where holley recommends you start at. Then, i would leave the vacuum advance unhooked and try to figure out if the stalling is due to outrunning your fuel supply. Once you get it where it will sit and idle as far as fuel supply, throttle stop, and idle mixture screws, i would make sure the base ignition timing is correct before hooking the vacuum advance back up. You should be able to set your base timing just by cranking it regardless of whether it has fuel or will start anyway.
I had a distributor that had the timing advance set-up seized, and another one that had the timing advance flopping around uncontrolled. Either condition won't help.
It might be quickly running out of fuel.
It has those access plugs on the top of the float bowls, leave those off, after it dies see if there is still fuel in the float bowl.
If it is using the original mechanical pump, I would convert to electric, although the mechanical one should work.
Sloowwwww progress, only had about an hour or so this evening. Pulled the throttle cable and backed off the throttle stop. Put the idle screws all the way in and backed them out 1.5 turns, and checked the float level. All in spec with Holley recommendations.
Was able to tweak it into a slow, searching idle that it would hold for several minutes in a stretch. Adding throttle still leads to a stumble and die; looks like a ton of gas is being added.
Backed the timing down from about 20 degrees advance, which it didn’t seem to like. But progress none the less
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