I have seen 1,000 hp run on these 1.76 set ups with no immediate problems in a 2600/2700 lb car...
Not saying i endorse this or not......my tranny guy says 800hp no problems with a 3,000 lb ball park range..
i now run 180 straight cuts but have a spare 1.76 in the shop..
i agree with the input shaft statement..spend $300 and get you one of those trans specialties ringless HI-FLOW input shaft..the one rated up to 1500 hp..
if ya want to stick with a hardened stock type turbo shaft...give me a pm i have one of those to...notice its in extra parts box...
Brian