Help with identifing this Oil Regulator please!

All,
I have an external oil regulator that in appearance is very close to the '73S/RS item. However the cast part number is slightly different.

PET lists the '73 as 911.107.015.00 while this one is 911.107.151 OR

A couple of us here are interested to see what it belongs to and what, if any, are the differences between the two.

Given they appear the same they should both fit ok, but there is no application listed for the 151 regulator.

Is the difference in something like opening temperature? Spring pressure?

Any help much appreciated.

NZ68T

That may just be a casting number and not necessarily a part number. Hopefully someone will have a known thermostat that may show whether or not that is the case.

Was the above thermostat ever identified? I have the same one on my '73.
I was just sold the thermostat below being billed as a '73, but it's significantly different from the one above. Can anyone help ID? (Ed :D)

Thanks for the help!

Kent, the one you pictured, to my memory, looks more correct. Never did figure out what the top one was, maybe a supercession??

Thanks for the help Ed. I've been scouring the interwebs and from what I can tell, the second thermostat seems to be the 74+ model that lives in front of the rear wheel with the longer hard lines running back to the tank. Does this sound correct to you?

The one at the start of the thread lacks the secondary (pressure releif ?) valve and has the holes for mounting it on the oil tank.

Sorry Kent, my mistake, the one you pictured IS a 74 and up, the previous one with the mounting hole tab IS the 73 that mounts to the oil tank. Somewhere I have a picture of the 73 version, can't find it right now.

Thanks Ed!