It looks to me that you have a 220a.
From what I know [ am not a Round body guy],the engine is
the same as the 219. [ same eng #]. The HP difference is in the head.
One has a compression of 7.6-1, the other is 8.7-1.
That explains the HP difference. [ there may be other small HP
contributing changes, {cam-timing ,etc.} , but SBs engine will do that car very well.]

The head ratio should be stamped on the head just above the gasket line, above the #2 plug.

Maybe some other owner could add to this.......