Yep....look at the distrib. Clean the grease off on the firewall side. Should be #s under there. If you have the acorn nuts on the top of the valve cover, you are looking at a 216/235. If none are present, someone has swapped out the 6 for a newer one.
I don't know about your 48 since it is an AD, but a serial number plate on a 46 is passenger side inside the engine compartment on the cab.
