Hi rpm engine cutout

[Blue72]

I've installed a Holley 670cfm 4-barrel on a 1972 350-cid. It has vacuum secondary, but I'm not sure how to test the secondary to make sure it's working properly. Suggestions?
Just recently the engine is cutting out at higher rpm with the throttle down, but I'm pretty sure the ignition is not the culprit. Could this be just a tank of bad gas? Any thoughts?

[six_speed]

We are working on getting a master Corvette mechanic on this board soon. Hopefully someone in the club will be able to answer your question.

Welcome.

[n2o408coupe]

3 possibilties, 1. make sure your fuel floats are adjusted properly so that there is plently of fuel in the bowls when needed. 2. try having someone manually open the secondaries by hand with the car running and working the throttle at the carb. 3. your motor requires larger jets and is leaning out majorly at the higher rpms with the current jets that are in the carb. Good luck

[six_speed]

Ebby, You are the man! [:D]

[Blue72]

I've flushed the fuel tank and refilled with good stuff. That made a world of difference, but also proved that I was running a little lean. Following your thoughts, I've made some slight adjustments to the fuel mixture, and she's back to running like she should - too scary. I'm doing a body removal pretty soon to do some much needed repairs to the frame, (I hate rust) as soon as I get everything back together, I'll take your last bit of advice and have a pro do a complete tune and jet. Can't wait. Thanks for everything!!!

[Blue72]

I've flushed the fuel tank and refilled with good stuff. That made a world of difference, but I was running a little lean. Following your thoughts, I've made some slight adjustments to the fuel mixture, and she's back to running like she should. I'm doing a body removal pretty soon to do some work on the frame. As soon as I get everything back together, I'll have a pro do a complete tune and jetting. Thanks!!!