Chosen Solution
What size are the nuts that connect the crossover pipe to the manifold
rickgerken3 the thread on the studs is M10-1.5 and the hex for the nuts is 17mm. Chevy is known to do some relatively goofy things, so you should arm yourself with a 17mm and 19mm socket. This answer may of course change, if you come up with some oddball model truck and engine. You missed that totally in your question. Year and model as well as engine size are always helpful in getting the proper answer.
I’m a certified Automotive Repair Technician, just started my own business called: Mike’s Mechanix in Hampton Roads, VA. I’m about to be working on a Chevy S10 tomorrow for a customer, intake manifold replacement actually. I’ll check the sizes for you and repost tomorrow! Should be a 10mm or a 12mm though
