"DANGER, WILL ROBINSON!!!!!!!" DO NOT remove those bolts! Yes, they're bolts, but they hold the oil pump mounting bracket on inside the crankcase, not the pump, and it was installed at the factory, using a very precise alignment fixture. Then the heads were cut off the bolts so nobody could tamper with it. It needs to stay put. On the crankshaft side of the bracket the oil pump plugs into, there is a setscrew and a lock nut. Loosen the nut, back the tapered setscrew out, and the pump will slip out of the fixture. The alignment of the pump with the bottom of the distributor shaft that drives it is very critical, and that bracket is the key to getting the pump housing lined up properly.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!