Bolt-on vs. bolt-on an LS1 wins hands down.

An LT1 would need the following just to equal a dead-stock LS1, and I'm talking about '98-'00 models, the '01/'02s were blessed by God himself...LOL:

-cold air intake
-bigger throttle body
-1.6 roller rockers
-.500 lift cam
-shorty headers
-cat-back exhaust

All of the above components are already on an LS1 in stock form, on top of the fact that it has better flowing heads; it's stock air intake, bigger T.B., 1.7 R.R's, .500 lift cam, freer flowing manifolds, and better exhaust are superior to a dead-stock LT1. And by bolting on components onto an LS1 like a lid and LT's, the LT1 falls behind again by virtue of it's weaker flowing heads and Optispark ignition that isn't as good as the LS1's coil-per-plug design. Strength-wise the LT1 only has 2-bolt mains in F-bodies/4-bolt mains in Vettes, all LS-series blocks are 6-bolt mains. Some prefer the stronger iron block of the LT1 and it's easier to machine since it's based on the traditional SBC, but you can resleeve an aluminum LS block up to 455ci last I read, while an LT1 I've only read being taken as large as 401ci and that's maxing it. There are also iron-block LS-series engines as well. Plus the LT1 was only around from '92-'97 so as the years go by, some of it's more unique parts will be harder to find. The LS-series engines are the present and future, but dig into both the LT1 and LS1 and they are equally capable of putting serious #'s down.

Early LS1 cars are also getting to be within the reach of enthusiasts and are still in decent shape, while older LT1 cars, though even cheaper, have probably been beat to hell or are just falling apart due to it being a G.M. product.

My LT1 laid down 278rwhp and 302 rwtq with just a cutout and CAI on the former TuneTech Dynojet, then 2 years later it only put down 260rwhp and 281rwtq on the Hybrid Performance Dynojet with the addition of a T.B. foil and 160* thermostat, so I don't know which to believe. I'm still slow no matter which number I stick with...lol.