I am parting out with my 305 TBI and putting in a 350 HO. I have the 700R4 transmission with 128,000 miles on it. Would the trans be able to support the new power? Would I just need to get the trans rebuilt? Or would I have to get a difference or new trans?

Thanks

Should be ok. You might wanna consider a good rebuild pretty soon though. The 700 should handle what your putting to it just fine, but it might not last too long with that high mielage on there.
Good Luck!