4bbl intake question

If you use a carb like a 390 cfm Holley with a vacuum secondary and tune it to the engine it should work ok especially if you do some exhaust mods. I have seen hot slant 6 engines that ran a 750 cfm thermoquad very sucessfully. It all depends on how much you want to spend and how fast you want to go. Check out slantsix.org and google slant six there is a wealth of info out there. The resident guru slant six dan is a walking encyclopedia on the slant 6. I believe that by saying if you keep your stock slant 6 below 4500 you should be ok if you put a 4 barrel on it. If you arent going to do any other mods I would consider a factory Super Six setup with a factory 2 barrel and freer flowing exhaust manifold AND very importantly the kickdown linkage you will need. I have seen complete setups carb, manifold, linkage, and air cleaner for between 150-300 bucks. If you install the 4 barrel you have the high frig factor of fabricating a kickdown system which you must have or will eventually wind up lunching the trans. Last time I saw the price on the Lokar kickdown cable for your application it was 80 bucks. Price everything out before you go for it. Slant 6 stuff isnt like small block chevy you will be paying a pretty stiff price for new /6 stuff.