My 1987 chevy s-10 had a old 2.5 4 cyl. now has a 350 cu.in. with 300 horse power.has a edelbrock performer intake with a 650 edelbrock carb.
tranny is a 700r.

Nice. I also have a 87 with the 4 banger. I want to swap the engine out to a 2.8.

http://eshop.advanceadapters.com/commerce/catalog/product.jsp;jsessionid=794F93853086A362D449620217E 34CDA?product_id=2608&czuid=1083637341010
is a manual for swapping your S-10 to a V-8. It tells everything you need to kow, including OEM part numbers you can use for the swap.
My son and I built an 84 S-15 Jimmy 4x4 with a 350, TH400 trans, with a B&M stage 2 shift kit.
We loaded the engine with a roller cam, cloyes gear drive timing set, with a Weiand Team-G manifold and a Carter AFB 625.