With a C6, I would think a vacuum secondary carb would be best for drivability and gas mileage. I just took a 650 DP off my Mach 1 with a 390/C6 combo and am replacing it with a Holley 770 Street Avenger. They have Electric choke and Ford kickdown. I’m in the middle of my rebuild so I can’t tell you how it runs yet but I’m hoping for good things.
http://store.summitracing.com/defaul...tt=hly-0-80770
Unlimited Speed has them on Ebay all the time for $310 or so free shipping. Summit price is $394.95
Tim