Not sure what Jerry was trying to tell you ? But that 3970010 Block is a 4" Bore Block some were 4-Bolt Mains . Most of the ones I have pulled pans off were 2-Bolt Main 350's with cast Cranks . Now that Block was also used in Trucks with 4-Bolt Main Caps . And in Corvette / Z/28's early 350 L-T1's and L-82's with all the good Forged stuff . Them 882 Heads started to be used in 1974 76cc Chambers the 1974 L-82 350's used them with Larger Valves . Some 400 SB's used them with steam Holes and Larger 1.60" Exhaust Valves .