Pretty valid, most stick LT1s will put out about 250 RW stock, and most LS1s 290-305 RW stock.
You could make those numbers on a stock bottom, but making 400 RWTQ you'd end up with probably 430 RWHP on an LT1. With an LS1 they make RWHP easily, there are hydraulic roller guys runnin 222/230 with ported heads making 422 RWHP. I ran about a 10º larger hydraulic to make 411 RWHP and 385 RWTQ, I had an ignition miss costing me about 600 RPM worth of power, so I dont know the ultimate potential of my combo.
Since the LS1 is Gen 3, rebuilding one to get a 381 etc is going to cost you a buttload of money. The LT1 is still SBC like, so a rebuild is pretty "cheap", if you wanted a 383. If you go LS1, expect to make your power on the stock bottom or expect to pay out of the rear end. Rockers cost $599 last I checked for them, sounds pricey doesn't it?
So basically hop up stuff is 2-3 times as expensive for the LS1. Keep in mind the LS1 is a very different beast in terms of power output, HP is high and TQ is not the same, just like the L98 is a TORQUE MONSTER but HP is seriously lacking, this is due to design.
As a point of reference, a stock headed 93 with a "bad tune" (supposedly) made ~400 RWHP with a 244/244 -114 solid roller. Fairly big cam but probably made bottom end power like mine did due to being a solid, stock heads is obviously not optimal but its "cheap."