1/4" NPT is 1/2" actual pipe size. Is also 18 TPI. Don't think that was stock... John Hervey's senders are 1/8" BSPT. He advertises as stock compatible, which would make sense because all the vacuum fittings and the thermostat bleeder screw are same. >From what I gather as DeLo late comer, stock compatible replacement parts used to be much harder to come by. May explain things like re-threaded oil pressure sending unit ports. My car didn't even have electrical sender -- PO had replaced with capillary tube to under dash gauge. Drilled and tapped to 1/2" NPT! Since dash gauge is 100%, can only figure he couldn't find suitable electrical sender. Remember that calibration is odd too: 0 to 80 PSI. I had no trouble finding 1/2" NPT to 1/8" BSPT adapter. Would imagine no matter what was done to block in the past, everyone should be able to return to stock compatible sending units now. Bill Robertson #5939 >--- In dmcnews@xxxxxxxxxxxxxxx, "Dave Swingle" <swingle@xxxx> wrote: > Jordan > > I took a closer look at your pic - looks like you have the right > part, and the right place, but something is amiss in your car. > Someone before you has probably removed the thread adapter. The part > you have as the "new" one is the common part used, the threads on > your old one look way too big. What does the block look like with the sender removed? > > The thread on the sender is 1/4 inch NPT, very close to metric M-1.0 > pipe thread. > > Dave S > > --- In dmcnews@xxxxxxxxxxxxxxx, "Dave Swingle" <swingle@xxxx> wrote: > > There are two oil pressure sending units. The large one next to the > > oil filter is the sender for the gauge. The small one above the > > catalytic converter is for the oil "idiot" light. Sounds like you > > have the right thing but are trying to put it in the wrong place. A > > common problem....... > > > > Dave S > > > > --- In dmcnews@xxxxxxxxxxxxxxx, jordan rubin <nuttenschleuder@xxxx> > > wrote: > > > Hello all: > > > > > > > > > For those who enjoyed my oil change howto, there > > > was a second job i was doing while the oil was empty. > > > > > > It was established that my oil gauge was at 80psi > > > because the unit it connects to was broken. > > > > > > I was positive this is what needed replacing > > > shown on left with wire next to area without oil > > > filter > > >