honestly, if you get a pre LS1 f-body, you would be looking at mid to low 14's and MAYBE if the previous owner took good care of it and did small mods to it, high 13's. brand new, they were running those numbers.. so most likely 14's...iirc.
with a supercharger boosting maybe 5-6 psi idk, you'd have ~400hp, (or so they claim.)
honestly, if youre gonna get a LT1, dont plan on a supercharger unless youre gonna get a rebuild with it.. of course unless you just want to fk around.
id spend the extra 2K for the car, and get a nice un-abused, low mileage one if possible.
remember, you can always add on a supercharger but you CANT change a car (for 2K~ish...)
my insuracnce @ 20 yo MALE, in hawaii, full coverage, theft, etc...costs 2K a year.