can you clean off the stamped pad?

if it is 8A205095, then it was/is a Plymouth B-body

bellhousing doesn't matter,
23-spline = 383 2bbl (anything but RR/GTX), 383 4bbl (anything but GTX) or 383HP (RR ONLY)
18-spline = 440HP (GTX ONLY) or HEMI (RR or GTX)