The reason I suggest the LT1 is I have gone both ways and the LT1 was the easiest and cheapest to do. Not to mention not having to cut anything excepts wires and exhaust to make it work. Plus the stock factory guages will still work and you can put most any transmission you want made by GM in it including the stronger than an ox TH400 built to pull a locomotive. The LS1 block cannot be bored out more than .010 by factory specs and the price of stroker cranks are through the ceiling for LS1 engines. The LT1 can be bored .060 oversize and SCAT cranks and rotating assemblies are inexpensive for the LT1. Honestly, I went down the road of the optispark problems but only had to replace it once and never had a problem with it after replacing the optispark only.

Which ever way you go, you are going to have a stout setup. You might even start thinking of looking at the LS2 engine GM has available now.