im at a loss on his one

Wait a sec.

I wasn't paying very close attention before, but when you mention back throttle plate...

This is a Holley 390 4bbl, isn't it?

There's lots of places for vacuum on a Holley, I think there is a port for the power brake booster on the back, too.

You have to make sure that the front throttle plate closes completely, not just if it opens and closes. There should also be an extenal throttle return spring on it. (Actually, it should be a double spring, but that wouldn't cause your problem)

You have to go at this one step at a time, completely eliminating each possibility as you go- be thorough.

You are at the throttle plate, be completely sure that it closes all the way, and that the return spring closes it. Then get it running, and spray around the carb throttle shaft, and all vacuum ports. Listen for a change in idle speed as you do this.

The engine is just a big air pump, it can't run fast (pump air out) unless you are letting air in.

 

thanks lwb,

it looked o me like it was closing completly, but i guess im not positve, i will try spayin everything again, and see if that solves it. i appreciate everyones patience with me on this, im jsut really frustrated at this point, it just doesnt make sense.

 

gotcha thanks glenn