Carburetor problem

[fundadtn]

I changed my 1 barrel carb slant 6 to a 2 barrel manifold but instead of the small block 318 type carburetor, I put a big block 383 type Holley 2 barrel on it. I bought the carburetor on Ebay, and I knew it would need rebuilding. I put a rebuild kit on it, and it still has a hesitation problem. (I cranked the engine before I rebuilt the carburetor and drove it) I have tried the mixture adjustment and just can't get it out. When you throttle it idle it accelerates good, but under a load (driving) it has a hesitation problem and will die sometimes when I am trying to take off. Also when it is operated on a slant (passenger side lower than driver side) the engine stalls and won't pull. I didn't reset the float level, and the guy I bought the carb from says it ran well when he removed it from his Aspen. I noticed when I disassembled the carb it didn't have any "BBs" in it. In the old days I rebuilt a lot of Ford Holleys and they always had "BBs" inside the carb. Once you get the engine RPMs to operating range the vehicle runs great. I can find NO vacuum leaks. It is starving for fuen, when the choke is pulled out a little it runs better on take off. If you know what I need to try next, or know a carburetor expert that can tell me, PLEASE email me at a_tim_porary@fastmail.fm (that's .fm not .com or .net) Thanks for any help you might have for me.