well i can't use a manual book to tell me whats the problem because my engine ain't the stock.its a L20B w/ webers,headers.......so thier is other possibilities other than normal..??

see the only worrie i have is that when i need power its not there because the engine is ####in'up

It doesn't matter if it's a stock engine or a race engine ... all the same principles apply. Get MOTOR manual (the big one that covers all makes) and look through the troubleshooting section.

One of the most common causes for the behavior described here is a bad accelerator pump. See the tech article Carb adjustment, troubleshooting, rebuild and inspection -- look at the "Accelerator Pump Test" section. Your 620 carb will look a bit different, but the test is done the same way.