I have a problem with my Holley 600 (4160)
Same problem...........
Solved with a 1/2" black phenolic spacer.....I already had a drop-down base.......With the half inch spacer, I didn't run into any problems with kick-down or throttle linkage.
Nice starts now when hot, and absolutely no boiling. I'll save the boilin' for my potato's. 8)