sbc identification

I have a small block engine that I bought to rebuild. It is a one piece seal block with a casting date in late 1988, casting # 14093638. When I took it apart it had flat tappet lifters in it. The lifter wells are nearly 1/2 inch deeper than an early 70's block. I need to know if this was made for roller rockers, as I understand that Chev. changed to rollers around this time. I don't know the history of the block before I got it. How can you tell the blocks that were made for rollers, as opposed to the earlier style?

It sound like you have one of the first equipped with the roller cam set up. Does the valve covers also have two bolts in the center instead of 4 on the outer edges? My guess is it does.

If it means anything...my 88 Chevy pickup has roller rockers