I tried fitting my new Shradek 26 mm oil pump into the (half) engine case today, and found that the rotor stud bottoms out against the cam end, and the rotor sticks out from the pump about 1.5 mm.

Here's the new pump (left) compared to the old pump, also a Shradek. The new pump has a deeper body. Is the new pump wrong for a GA case and/or a Web Cam?

New pump box label.

Also curious why the fit between the cam slot and the pump rotor stud is so sloppy--about a mm gap.

Schadek Type one pumps are modified for the T-4
1) With the pump out of case: Does the gear stand proud/up like in the pic 1? This answer should be EZ to test and should be no.

2) Looking at the drive gear from the Top, (Gear side/ not drive side) Is the the drive "shaft" flush with the top of the gear? Most are pressed flush or near flush with top of gear as part of the Mods for T-4 as part of the shortening the shaft to the timing gear clearanceing

3) Is the end of the drive shaft (gear) radiused? This is need to fit the cam gear hole and get the correct depth/clearance

4) Looking at the cam gear I appears to be touching the pump Housing too? This part of the housing is also shortened if needed for clearanceing

-On the body you have to measure the depth to make sure the "snout" clears the cam bolts. If not you have to remove more material.
-The shaft can be pressed into the gear futher by using a bench vice as a press. You want the tang well engaged but a good .020"-.030" clearance.
-The pump drive tang has always been made this way on both T1 and T4 pumps, it's normal.

Looking at the pump body it looks like the wrong pump, it has to be the pump for a T1 3 rivet cam, that looks like the deeper pump for a later 4 rivet cam.

Thanks, everyone. I fixed my clearance issues by pressing the pump drive shaft fully into the gear, and by shaving 0.75 mm off the pump protrusion for clearance with the end of the cam shaft.