Another guess my SB 340 et 1/4 mile :)

Locking out a dist is a hole different thing. no mechanical advance in the dist. Were you set the dist is were the timing is from idle to full rpm(Don't let this confuse you. you don't have it, so don't worry about it.)

you have your initial set, now slowly rev the eng until the mechanical advance stop advancing. depending on the springs (used in the dist) it should stop advancing between 1500 and 3500 rpm. This is you total advance.

If it likes 24 grate but total shouldn't be above 34-36