triples secondary

Alright im looking to go triples as soon as my dd is done. I have a 94 2wd and wanting to make a fun street drag truck. Right now i have two he351 over a older schwitzer 66mm secondary, the turbine is 79/90 and a/r is unknown but looks tight. Woundering if i should just go with a s475 box turbo and save the hassle (roughly same size turbine if not more efficient)? I picked up the schwitzer 66mm for 60$ and it has a bigger shaft in diameter than a s474 that i have laying around that came off a 3406 or c15. for what its worth seems like it could take some abuse, looking for 1000 horse +. Any and all advice would be greatly appreciated thanks