Which bushing do you have on the distributor? If it's not the black one, install that and reset your timing and carb setting.

If you slapped the distributor in as delivered, it's got a garbage tune on it. Also change the spring from teh garage door openers that are on it to a light silver and blue spring.

It's missing a bunch of power with the doggy MPH and is a soggy banana done low is my bet.

If that thing is tuned with proper fuel delivery and running right it should go low 13's easily. A 360, xe268H LD340, 350ish hp on a dyno in a 3300# a body ran over 104 in vegas in bad air. OP has got more cam from a lift perspective and better heads.