A good idea would be to "search" this site for topics dealing with the various ways of determining the exact year of your engine. Once you know the year, you can get specs for torque, horsepower, and of course the factory recommended rpm's.

The topic of full pressure versus low pressure is also covered on the stovebolt site with a "search".
In general the common "concept" of full pressure being better than low pressure is a FALSE one. "Full pressure" Chev truck engines occured around late 1953 and were available in 1954. The "full psi" oiling system basically included a new passageway in the crank rod journal to provide oil from the new oil pump, thru the crankshaft, and under pump pressure to the rod bearings. The OIL GAUGE would READ a much higher psi than the old system and thus the term "high pressure".

In the old so-called "low pressure" system the oil to the lower engine was provided in a 4-Way method. 1) The oil pump to the mains at full psi 2) Dippers to scoop oil to the rods at low rpm 3) Squirt nozzles to hit the dipper scoops at higher rpms and 4) Splash from the dippers/squirts to lube the cylinder walls & wrist pins. This system would READ a lower psi on-the-gauge BUT IT WAS NOT an inferior or bogus system.
The FLOW of oil to the rod bearings was VERY high and the centrifical force of the oil on the rod bearings that had been squirted into the rods was extremely HIGH in psi! The so called "low pressure/high flow" system was excellent for the 216 and 235 engines, it wasn't really lower pressure where it was critical!!!! It was super for the babbitt bearings and kept many a stovebolt running into the 21st Century. (It was also quite expensive for Chevrolet to produce)

BUT in the mid 1950's the race for more horsepower ment a race for more rpms' and the old dipper/trough/squirt system could not keep providing good engine lube at the 4000+ rpm range. The expensive scoops/troughs/squirts could not keep up at higher 4000+ rpms and GM switched over to the oiling type system they had for the GM trucks. The need for hydraulic lifters in Chevy cars also spelled doom for the old 235 oiling as better oil routes were needed to get oil to the hydraulic lifters. New use of "oil filters" also became popular by mid 1950's and the filters caused a need for consistantly higher psi to overcome the resistance of flow thru the filter media. Combine all this with an expensive production cost and GOOD-BYE faithful old dippers/troughs/squirts ...aka "low pressure".

Your rear end is very robust and should handle high rpms (3000+ range) better than your old engine. The truck rear ends were often used in the 1960's for street racing on cars to get a lower rear axel ratio and provide a very tough rear end.

Maybe the whine in the rear end at speeds above 2500 rpm is a call to have the rear end checked out. You can lower the rpm's by switching to taller diameter rear tires. But maybe your rearend neads to be opened and examined: clearances checked; look for an imbalance in the drive train??

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Vintage Chevy Forum