Tired of TBI issues, what size carb???

[zombiescustoms]

I have a 1987 one ton, with a 454 turbo 400, mild RV/ towing cam with TBI problems, and I'm tired of throwing money at it! So I'm going with a carb and intake set up and a fuel regulator to use the stock electric pumps. I'm going to be using the weiand 8017 manifold but need to know what size carb I should use, I have a 585 CFM Holley from my 327CI but I'm thinking im going to need at least a 650, any suggestions??

It will also have a MSD dist. and box, and a set of small dia primary headers.