Stumble off idle -

[Grubby]

I will attempt to answer as many questions as I know;

timing is set a 16 deg @ 800rpm and 36 deg alll in before 3000rpm. No vac advance.

The cam is mild but I don't know the specs. The engine dynoed at 480hp. I would say it is a pretty typical Joe Lapine build for ERA.

I checked my vac gauge on my 2003 GMC Sierra. 17 inches at idle.

With the Cobra at 800rpm it has 10 inches.

Confirmed that there is .015 clearance after WOT on the accel pump. It actually had maybe .020 so I adjusted to .015. And the moment the linkage moves I get fuel from the accel pump.

The carb is a Holley 3310-11 1045 - 750cfm.

Last summer I determined the secondaries weren't opening and went through the excercise of finding the right spring. I replaced the Black with a Purple. The secondaries come open cleanly after 3000 rpm.

I did try richening the idle screws 1/2 turn after best idle. No change was noticeable. They are now set back to best idle.

The car will die if the idle screws are turned all the way in.

Throttle plates do not have holes drilled and secondary plates look like they are completely shut.

I will place an order for a 31 squirter. That was clearly not the problem and I will go back.

Don't know the jetting. The plugs and side pipes are a deep tan color. I assume primary jetting is correct.

I installed new lifters last fall to get rid of some valve train tick. They are hydraulics and were adjusted at that time. Installed without removing the intake.

The stumble is not new. I am just working through my list of items to make the car perfect. The stumple has been there since day one.

Back in the mid 90s I was ASE certified master tech. I was a driveability engineer with GMC truck. I have always worked on my on stuff, but have little holley experience and no stock of Holley parts.

John