Forgotten.... What thread size are head studs into the block ?

[Andrew Rowe]

Correct me if I am wrong but the 50lb / 80lb pressure units go with their respective gauges , but also remember are there not two different types of oil pumps that can go in the sump , one high pressure and the lower pressure ones that the carriers use ( 50lb ). Macs auto in the States make repro sender units from ,I think Mexico , but these are for the 80lb units, so save your old low pressure units for reuse.