I was at a auto parts store, and they were asking the make and model of my car. They had a Caprice, Caprice Classic, and a Caprice Classic LS. What is the difference between a Classic and a Classic LS?

Also, do yall think I could make a 4.3 run just as fast as a stock 5.7 with some modifications? Or should I just go ahead and buy a 5.7 and swap the motors?

#1. Trim levels.

#2. Not without some form of boost - Blower, turbo, ectectera. 85 cubic inches is a lot to make up in simple refinements. 1 HP per CI is fairly respectable for an N/A engine. 2 HP per CI is resonable for a boosted engine. By that crude math, without a means of blowing through the intake, making much over 270HP with the L99 would be a real chore. The iron-headed LT1 is already making 260HP in stock form, with a tame cam and poor intake/exhaust tracts. And highway fuel mileage is the same for both engines. A little work on the iron-head LT1 and it makes 300 HP very easily. More serious work gets you 360-ish without too much stress.

#2A. As fast as a stock 5.7? The speed limits in most places are either 65 or 70 MPH. Either car can do it easily, so I suppose they are just as fast as each other.

Oh I knew what else I wanted to ask. Someone I know has a super charger for a Buick somewhere near the year of my car I think. Just out of curiousity, would I be able to make that work for my car? or no?

Not without more fabrication, welding, filling, and machining than it would be worth. That blower is designed to make pressure into a 231 CID engine. It may have trouble maintaining even 1 BAR on a 350 CID engine without seriously overspeeding the blower rotors.

That doesn't even address the need for a 2 BAR MAP, PCM reprogramming, different injectors, the forged internals, and everything else required to manage the boost.

Well, is there any super chargers that I could get for my car? Or no?