Royal Pontiac was a dealership on Main Street in Royal Oak MI.

There were a few tiers of performance packages offered. Off the top of my head, remove heads, mill, gasket matching, recurve distributor, thinner head gaskets, tweaking carb, cam changes, rocker arms...

There were a few packages up to installing Ram Air induction to non ram air cars, steeper gears..etc.

Typically Firebird and GTO oriented.

http://www.legendarycollectorcars.com/2011/04/1968-pontiac-firebird-and-royal-bobcat/

Is the engine correct to car? Any other docs? If it is, and you have the PHS, may be worthy of checking a few things if the car is original. CC the heads, check the distributor..measure head gaskets...any other things performance oriented. i wouldn't recommend disassembling just to verify...but could be a valuable car if the engine and trans is original.

I have a spreadsheet somewhere of all the Royal cars pre and post Bobcat. Engine size, trans, rear ratio, ET, MPH, size tires (stock/slicks)