I'm running a Edelbrock Thunder 800 on my 408. All I had to do was set the idle and idle mixture. I paid $100 for a tuning kit with jets and rods. When we ran it on the chassis dyno the AFR was right where it needed to be so I sent the kit back! I have no complaints with the carb at all.
I run a 800 AVS carb on my 410 stroker and it is awsome. 22mpg with 3.91 gears on a run. Still runs 11.4 qtrs. I think a new AVS with the new boosters would be even better