Carter Carb Help Question

I just put a professional rebuild carburetor on the 61 Caddy. I set the carb by the manual manual step by step. I set the timing, checked the dwell and replaced the plugs ( old one looked really good) . It idles smooth, not a shake one. runs nice when you do a slow acceral, but when you go to step on it like pull out in to traffic it stalls and runs rough, almost like it loading up or stumbling or the timing is not advancing. I am at a loss of ideas what could be wrong. Any ideas or help is greatly needed. Thanks Dave

Look in the Cad forum, please do not double post, thanks.