Since it sounds like you've already got a good starter you can do what I did:
I just drilled and tapped the block on the old race engine so I could use my high dollar mini starter - worked fine - the starter makes a nice drill bit guide to get the drilling started - use the one bolt to hold the starter in place tightly, then get a drill bit that fits nicely in the hole of the starter, drill in the block until you've got a nice start of a hole (like a huge center-punch dimple) and then pull starter, swap to the proper size bit and drill the block. Clean it, tap it, clean it again, bolt up and enjoy...
1985 S10 old claimer 355, TH350, 2800 stall, 9" rear 3.50 spooled, 11.50's - fun on the cheap (building a turbo'd vortec 355 for it over the next year)
1996 S10 ext. cab street beater - Carbed 406Ci, built 700R4, 2800 stall, and no real traction to speak of
For all your parts needs call KC Speed Shop at (816)434-8145 and mention V8S10 for discounted pricing