i have a 88 s-10 ext. cab and it has the 2 pc shaft. however my room mate as a 87 and it is the single cab with the 350/350 and i believe they ended up finding a shaft for it.
you can use the mounts for the motor and i want to say we needed to find a cross member for his truck, but the body was off the frame so it was not as much of a pain to do his.
look at v-8 swap there is more info then you might think out there and on this site then you might want to know.
use the search button at the top and do a search for S-10 tons of links should pop up for you