I think you have a 80670 carb?
If that's the case, you should have a .031 primary pump nozzle? That should be plenty with a "regulation" single plane intake plenum volume.
With that said, the as delivered #65 primary jet may be lean for you, especially on a big block? That carb should have a "plain" secondary opening spring also. Although I'm not sure how early/late the hesitation is, I think I'd try at least a "yellow" spring to bring the secondary's in a little earlier.
I'd be remise if I didn't ask what your timing is set at. I hope you're pushing the initial as high as you can without knock/ping issues along with not running the total too high...34/36*. If you're running anywhere near stock timing numbers.....just throw out my carb suggestions. Timing first, then carb adjustments...it's gotta be done that way.