late model engine swap?

[68c10owner]

I`m going to need a engine for my 90 pretty soon. I was just going to get another TBI 350 core and rebuild it but I started thinking about swapping in a later engine, either a vortec 5.7 or a 5.3 or 6.0 GEN III. I would really like a 6.0 in my blazer. I know someone makes either a spacer kit or a converter to adapt the early trans to the LS1 flexplates. Anyone swapped in a later engine able to offer any input? I will probably have to wait untill next year if the engine lasts that long but I wanted to get a idea of what I`m up against. My only reason for swapping in a later engine is to get a little more power. My old 99CK ex-cab had a vortec 5.0 and that thing ran really good. I know trhe vortec series would beeasier to swap in but the GEN III`s make more power. The only other mods may be headers and a air intake. This is a daily driver, nothing more.