All of a sudden, unless I keep my foot on the pedal the idle rises and falls and eventually sputters out. It will only fire up if I pump the pedal a couple of times first. I also noticed a bit 'popping' from the muffler.

In case it matters, my base timing is only at about 8-10 degrees. Much more than that and I get alot of ping at WOT. The carb is a Holley 1850 VS.
Thanks,
Jon

JSD MOD 23/09/08

 

you've got a big vacuum leak.

 

Thanks Sonix. Yeah, that was my intial thought. This all started a day after one of the headers started leaking. I thought that I had dislodged a hose while changing the header gasket (which is still leaking)

The only Vac. hoses I have are for the brakes, PCV and one out the front of the carb (no 'timed' port). All seem fine. I changed the gasket between the carb and the intake to no avail. I did change the intake this past winter. If I had a leak there could I hear/feel it?

Thanks,
Jon

 

You might have a clogged fuel passage inside the carb. Check your float levels as well.

 

probably a vaccum leak...