You didn't mention what rear gear or the stall speed of the torque converter you are running. If stock, the rear is likely a 3.23 which will be OK with the Torker off the line but it will be its happiest at higher rpm. Same with the torque converter, I think stock it was a 10.5 or 10.75" which you can power brake up close to 3000 rpm off the line. I ran a torker on a built 383, stock converter & 4.10 sure grip Roadrunner and it ran great. So if you're running otherwise stock trans & rear, your 383 will be happiest mid-range & up rpm-wise.
100% agree on your leak, I'll bet the carb was fine, the issue was your spreadbore intake.
Later, Jim