Need torque specs 1988 Chevy silverado for main bearings and rod

Those values and most everything else you need for DIY work are contained in the Haynes manual for your vehicle. We have one with each of our vehicles and not only give you the info needed to do repairs yourself but also get an idea of how much work a specific repair should (or shouldn't) cost.
'88 Chevy pickup manual
You can also buy these from auto parts stores for a few dollars less and sometimes on eBay for even less.