Those are the two main carbs I'm looking at right now. I'm also considering a 390 quadrajet off an early 4.3 v6. I'm also taking gas milage into consideration when choosing a carb, that points me to the holley 350, and yes I have looked into efi, but $1200 for a kit is to much and I don't have the skills right now to modify a 4.3 system to work but I might in a year or two, who knows. I am changing to a higher thermosat at least for this winter so that should help a little, and by next spring I hope to have an electric fan to hopefully get a few horses. Basicly should I wait intill I have a carb and heat plate for the clifford and do it all at once or can I go ahead with out sacrificing performance and drivability.