No need for a 4 bolt main block unless you're doing 8 second 1/4 miles or pulling trees out of the ground. I have seen many 500=hp 350 engines with 2 bolt main blocks over the years, It's your S-10 do what you wish! As for me, I am pro GM so no foreign stuff for me unless it's the only place to get parts I need. I have a 4x4 V8 powered lifted Astro van so my S-10 is my winter vehicles, but I will still fix it all up.