My 216 operates at 2.5 psi. The FSM gives a range of 2 - 4 psi for fuel pumps.
What kind of fuel pump are you using? If it's electric, buy one that operates in the correct range. If it's mechanical, figure out why it's putting out such high pressure. If it's an old, original style pump, send it off to Then and Now Automotive to be rebuilt.
www.then-now.comThere is no reason you should have to run a regulator on than engine.