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235/261 Pressure Oiling

By Bruce "Phat" Childs


When you're runnin' down the road tryin' to loosen your load, does it ever worry you that your trusty ole Stovebolt may not be getting enough oil pressure? Ole Phat has fired up the shop and will walk you through turning your favorite 235 or 261 into...

A full pressure oiler!

Tool list Parts list
  • 9/16 drill bit
  • 21/64 drill bit
  • 3/8 NPT tap
  • 1/8 NPT tap
  • 3/16 drill bit (or close only for starting the hole)
  • Remote oil filter
  • 1/8 pipe plug
  • (2) 3/8 NPT X fittings


This is how I have done the full pressure oil filter on the 235/261. I don't suggest you do this unless the motor is completely apart for a rebuild. With the drilling and tapping there will be too many metal chips to do this on a motor that is already built.

    All of the drilling and tapping will be done on the oil pump side of the block.


Step One

    Get a 1/8 NPT tap. Now, go about 1.375 in the hole (being careful not to damage the threads for the pump fittings). Tap and install 1/8 pipe plug. This will plug the passage to the mains.








Step Two

The block on the oil pan flange -- note angle of tapDrill the hole    Put the block on its oil pan flange. The next hole you will drill from scratch and may be a little scary for the first timer. Just take your time and look at the pictures. I tend to drill this hole a little on the high side so you do not get into the fitting for the oil pump. Start with a 1/8 drill bit on a slight angle. (see angle of tap below). Go to a 3/16 and then to a 9/16 drill. Be careful and try to keep it lined up straight with the oil pump passage. Now, tap the hole with a 3/8 NPT tap being careful to keep the same angle that you drilled on.






Step Three

    The next hole that gets drilled is the hole that used to have the bypass filter and oil pressure gauge hooked to it. Take your time and just drill this one out to 9/16. Tap for 3/8 NPT also.


Step Four

4 -- Centered on the Passage     The next hole is drilled about halfway between the last one you drilled and the flywheel end of the block. Get the hole centered on the passage. Drill it with a 21/64 drill. Then tap with a 1/8 NPT tap.

The 21/64 drill in action








Step Five

    You may choose to not drill this one if your filter has a place for a 1/8 NPT to plumb your gauge. I have done them both ways. We use the Trans-Dapt remote filter in our shop, but others will work. There are other ways to do this but I have found this one to look and work the best.


Fittings in -- you're DONE!







    Total time to do the job is about 1 hour. (It took me longer to do this article!)

    Have fun and be safe!

Bruce Childs (aka Phat)

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