350/290 HP Timing and fuel delivery

I have a 1983 Chevy Silverado with 140k miles and a 350/290 HP crate engine I just got through putting in and a 700R4 Tranny and 600cfm Holley (with kickdown bracket of course). My problem is that I am not getting the throttle response I did on the worn out 305 I took out, I know I should be getting more response but it doesn't feel like I am getting what I paid for. I think it might be the timing or fuel delivery problem, b/c I fixed the t.V. Cable and it shifts fine, but when I give it gas on first it hesitates and the carb hisses and then it goes. I know that is not what it is supposed to do, it is supposed to spin the tires not hesitate. Which is it or both, if it is timing please tell me the best timing BTDC for this performance crate engine without advance (b/c I don't have a timing light) and if it is fuel delivery just tell me how to fix it so I can get that engine to work the way it's supposed to.
Thank you for your time.