427 GM Oil Pump - #3964255 vs GM Oil Pump - #3946023
 

GM literature lists oil pump c/w pick up - GM #3946023 used with 427 GM Deep Performance Oil Pan, 6 quart - GM #3879633. Other GM publications list oil pump c/w pick up - GM #3964255 used with 427 GM Deep Performance Oil Pan, 6 quart - GM #3879633

It is my understanding that oil pump - GM #3964255 came with the pick up that was not spot welded to the pump, allowing for optimum adjustment. Whereas the GM #3946023 came from GM already adjusted and tack welded.

Can anyone confirm?

Thanks!

Btt

I received clarification on the differences. It appears that GM #3964255 is the correct oil pump that I need to located for the GM Deep Oil Pan #3879633.

GMPARTSWIKI lists the following description for the associated part numbers.

#3964255 Pump ASSY. (Oil) (Deep Oil pan Only)

#3946023 Pass. 396, Pump ASSY Oil


Thanks !

My NOS #3964255 oil pump has the pickup tack welded to the pump.

- Warren

Yes the 3964255 pump is correct for the 6 quart oil pan. I had the whole complete assembly, oil pan, pump, curved windage try and bolts. I sold this set for 1.000.00 about 5 years ago.

That is one sweet oil pump....very nice.