Block usage for early 11C L78 69 camaro

[nugeusa1]

Im restoring a 11C 69 L78 assembly date 1116 Jh per POP . My plan is to build a a open chamber L78 with 074 heads for now while i search for the born with block, it a long shot but its a local car and still hopefull i can find it. My question is would it be a 440 or 272 casting? Thanks for your help , id at least like to put the rite casting back in. Nuge. O,i do know their wasnt any open chamber l78’s , i just have a nice set of 074’s and thought id use them.