I'm am of the opinion the LT1 will lose. It's going to blow up as soon as he gets on it, LOL.
I would really doubt a stock LS1 running a 14.4. That's just not normal. I don't like the LS1, but it's quicker than that with a decent driver. An LT1, will have to add 100hp over stock to run with you. If this guy has what he does, it should have that and more. It's all tough to say though on the street.
Consistant 13.4's.

Set's a new best so now it's consistant? LOL.