I can't seem to pin point way my car dies when decelerating. It's a 305 lg4 w very mild cam, street dominator intake, shorty headers and a Holley 600 single pumper. Seems to idle just fine and drives well except when I am decelerating with the clutch pushes in. Almost acts like it running out of gas. Hard to restart I have to hold the gas to the floor and turn over for 10 sec or so. Has street fire dizzy as well. I have the timing set by ear because balancer has 12 oclock mark and new ting cover has 2 o'clock tab. All vacuum connections seem fine. Any help would be awesome thanks

 

Does it only do it under hard deceleration or does it do it pretty much any time you punch the clutch and brake at the same time?

 

First off, set the timing. I had the same issue with a customers dampener as you. I pulled #1 plug, inserted a hunk of coat hanger and rolled engine over by hand and watched the hanger until it was at TDC. I then marks the dampener at 0. I masked and painted a line to set timing with. Get that fixed first, then go from there.

 

Pretty much every time

 

If you just have it stationary/idling and stab & hold the brake pedal, what happens?

 

Ok I get on setting the timing properly

 

Pushing the brake at idle has no effect on idle rpm at all

 

Another thing, is this all the time or only when hot?

Also, are all these mods done at same time?

Is this an instant problem or constant issue?

 

Seems to happens when the car is hot now that I think about it. On going problem.

 

OK, it's not a leaky power brake booster issue, then.

If you give it a hard rev in neutral (idling fully warmed up, choke fully open) and let the throttle snap back closed.... does it want to die and then recover or does it just settle back to normal idle with no stumbling? If it wants to die (or almost die) and then recover, your idle mixture screws are set way too lean.

Beyond that it would be time to check the float levels in the carb. And to measure your fuel pressure is all the way up the RPMs at WOT (i.e. do you have a fuel pressure gague mounted where you can see it while driving).

 

Car goes right back to idling fine when reving in neutral. I hooked up a vacuum gauge last night and it holds a very steady 15hg. The carb has no float adjustments and don't currently have a fuel pressure gauge

 

All Holleys have a float adjustment. That's the next thing I'd check. If it's already too high it can get even higher on decel to the point it causes a momentary flooding.

 

I've got a brand new Holley that claims it has floats that never need adjusting. I could pull the fuel bowls I guess but there is no external adjustments