I have a Holley 80531 carb that came on a crate 502 on my 70 velle 454. It has run well until last Sat. Under full throttle, apparently the plug from the ignition module and pickup coil wasn't snapped on tight, and it came unplugged from the HEI cap.
Since that point, (after I replugged the module/coil pigtail) the engine has run rough. I since, have replaced the distributor (a new pertronix)and voltage regulator and alternator, because I suspected a persistant electrical problem. Still rough running and quits. Today I noticed after the engine quits, that raw gas is dripping from the shaft of the secondaries, and I also heard and noticed raw gas filling the secondary air horn above the throttle plate. Question #1 : Could the full throttle flame out have damaged the powervalve?
Question #2 : I noted carefully the rotor position when I replaced the distributor, but it almost still sounds like a timing problem. (except for the raw gas dripping)
Question #3 : I also noted ( it may have been there already) the intake manifold gasket above #1 cylinder has separated and a piece is sticking out. Can you "blow" an intake manifold gasket?
Sorry to be so lengthy, but I'm not sure if suddenly multiple problems just happened, or if one caused the others.
I really appreciate the expertise you guys bring to this site, it is so far superior to anything I have access to locally. Many thanks in advance for taking the time to read and respond!

tim

Hi Wes Colby! Any thoughts on the above?

If it did't backfire when the ignition quit I'd be supprised if it popped the power valve. If it's overflowing the rear float bowl it might have trash in the rear needle & seat. It'll run awful if a float bowl is loading over. I doubt the ignition shutting off with the throttle wide open would hurt the intake manifold gasket.
Howard

Thanks for the reply Rusty,

Is there a significant vacuum leak issue with the manifold gasket section missing? (There is probably about a 2" section that has broken off at the front and is protruding out.) Thanks for the help!

Tim

Tim,
If it's really sucking air through the place where the gasket is sticking out it'll run that cyl. lean and HOT. I guess MAYBE a big enough backfire through the carb might blow a piece of intake gasket out. You should be able to tell if the piece of gasket is the whole width of the strip around the intake runner or just a piece that separated and is sticking out. Fix the carb and check for an intake leak. Don't run it hard or much 'till your sure there's no leak. I think multiple problems probably cropped up at the same time. My probelms usually come in bunches too. Howard

Hey Rusty,

Thanks again for the info. Yes it is the whole width of the gasket sticking. Oddly enough I sprayed carb cleaner while the engine was running, and it really didn't smooth out or seem to make much difference like a significant leak would. I'll definitely not run it much until I replace the gasket.
I did set an old Edelbrock carb on and fired it up, and the BAD miss was gone, so the Holley definitely must have a stuck float or some debris in there. Edelbrocks seem so simple compared with the Holleys, but I have to say the Holley definitely steps up the performance (maybe only because it's an 850, instead of a 750 like the Edelbrock?
Anyway, appreciate the info!