Dude,you will have all the room you want.
If you can put a 4.3L V6 in a S-10 them you can easily,a small block is only 5'' longer and the same width.
You will need and good elec. fan but other than that you can use ever thing you have now(if you have a 4.3)but even if you need to buy some parts I bet 90% will be in stock at any parts store.
P.S. if you really want to be the man get a set of NASCAR goodies dash heads for the 4.3L and GMPP cam and intake
how does a 400-450hp V6 sound?