Timing Cover..."Stupid Question"

Sounds like you have timming cover with no marks. Some came like that,I thought only on 360's from some time in the late 70's. If so, they had a little bolt on tab that went on the pass side, I believe. It was attached at the top of the housing by two of the bolts. You might be able too get one at a dealer.If not I can probably find one in all my stuff for you, seems to me I picked some up at a swap meet a few years ago. Let me know. It's been awhile since i have messed with them. Hope this helps. Dave