Usually high output pumps are unneeded for the 216/235/261 straight 6s because the RPMs and power levels don't warrant it. Proper bearing clearances and a good stock pump will keep the pressure between 20 to 45 PSI. I'm doing a lot of research now into distributors and oil pumps for 235s because of a problem I'm having. Check out my 'lost oil pressure' thread for worst-case scenarios.
From what I've heard in the past few days, high-output pumps may cause the gear to shear off the distributor shaft, or other similar problems. Supposedly the distributor shaft and drive gear aren't designed to transmit the higher torque required to turn a high-output oil pump.
good luck
chip
