That's a 70s 2 pc rear main 350. Dipstick for oil is on driver side. Best block gm had for power as far as 350s go. Some 010s had added nickel content wich can be found under the timing cover. Shows a n with a number. My 010 went 8.89 at 153 with splayed caps and no block fill. They usually have a piston with a small dish and rounded piston tops at the rings come in arround 8.7 to 9.2:1 all have 5.7 rods some have the x rod wich some say is stronger. Cranks can be forged or cast those yrs. Most 010 blocks are from late 70s pickup trucks. Lift a valve cover off there will be a 3 digit code like 840 841 142 or something like that to tell what heads it has. Some head castings only came in 1 cc some in 3 diff ccs. Hope that helps someone.