You will find there's typical oiling dilemma with the pre-1992 R32 RB26 motors, as the surface exactly where the crankshaft meets the oil pump was machined too little, at some point leading to oil pump failure at superior rpm. This difficulty was solved in later on variations with the RB26 https://nissan-rb26dett-engines-f65329.blogrelation.com/37273249/the-smart-trick-of-rb26dett-engine-sale-that-nobody-is-discussing