Can anyone help???

[muskrat]

I got a 81 750L I installed a Mac 4 into 1 exhaust,and did a Dynojet stage 3 jetting kit (with a 130 jet) with open air cleaners (pods). I have a cackling noise @ the colecter pipe when I speed up and let off gas to stop. Any ideas what could be causing this?

[Billy Ricks]

I got a 81 750L I installed a Mac 4 into 1 exhaust,and did a Dynojet stage 3 jetting kit (with a 130 jet) with open air cleaners (pods). I have a cackling noise @ the colecter pipe when I speed up and let off gas to stop. Any ideas what could be causing this?

Sounds like you're a little lean on the pilot screws. Adjust them for the highest, smoothest idle. Did you synch the carbs?

[muskrat]

no not yet just got them installed just wanted to see if it still run. And how it will run.

[Billy Ricks]

no not yet just got them installed just wanted to see if it still run. And how it will run.

Synch first, then check your idle mixture, then recheck the synch. It could be either/or, or both.

[KEITH KRAUSE]

Like Billy said, adjust your mixture screws for best idle, then synch before trying to tune the jetting.
Also, the header gaskets should be replaced with any pipe change and torqued correctly/uniformly. Leaky gaskets will cause decel' popping.
Your stage 3 kit will also supply different air jets, pilot jets. You can try mixture screw adjustments, but larger pilot jets/air jets are generally required.