I have For Sale an Excellent Like New HOLLEY Vac secondary carb 770 cfm. It has a quick change secondary spring that can be changed in seconds to your specific needs. It has an Electric choke, 4 vacuum ports, Chrome fuel line with pressure guage port. This is a Holley Street Avenger # 0-80770.
Copy and paste the link below to see this carb on Holleys web site with specs.
https://www.holley.com/products/fuel.../parts/0-80770
This carb runs very good with no problems.
$300 takes it plus shipping.
Photos can be sent to you cell phone.
585-750-2982 please leave a message if no ans. I will get back to you ASAP