Mopar Magnum

If that was a chassis dyno, then that is pretty good hp. You lose about 25-30% thru drivetrain depending on trans condition and convertor slippage. That would equate to 350 hp or better engine hp. I'll bet your grandfather had some paperwork somewhere about the engine specs. (shoebox, or file cabinet w receipts) There are some good tuning tips for small blocks on this site that will really wake up a 360. Make sure it is putting out what it should. Get timing lite and vacuum guage for tuneup.