Hello  I reread Teds answer above and thought it was specs for spring so I didn't look closely.  Now think specs are for valves  OD and length for both types of pumps as they match up  to what I found.  

Someone on the forum should have a spare gearotor pump that can be salvaged for parts. I see them for sale occasionally on eBay; that's where I bought mine. It appeared to be in good shape, but I went ahead and bought the rebuild kit. 

Hello Members  I put up a question 7 months ago and would like to update it.  The cast iron georotor  pump I have is a aftermarket  republic  parts pump. I tried fitting a gear type pump bypass valve (or piston) into it, ( don't have a bore gauge small enough to measure bore) it was to large (OD .4965). Have another 292 with a AL factory pump, removed valve and it fit fine in cast georotor pump  (OD .493).  Length is 1.915 is  .030 less than gear pump valve (1.945). Al valve has 2 groves. Cast gear pump is smooth.  Trying to find a worn out AL georotor  to salvage the  valve from it. Have thought about having bypass bore honed and using gear type valve as plan B.

Thanks for quick replies Charlie and Ted. Will put nose to ground and look for a AL georotor pump. One I have has threaded plug on relief valve bore. Cos

This adds to Charlie's post.

While the valve itself is the same, the springs are different.  Here are a couple more links to past threads on the subject.
http://forums.y-blocksforever.com/FindPost154838.aspx 
http://forums.y-blocksforever.com/FindPost22736.aspx

Lorena, Texas (South of Waco)

In this thread, http://forums.y-blocksforever.com/Topic133095.aspx I made a statement that they are slightly different but didn't take pictures or try to describe it.  So they are not the same but I don't know that that means they won't work.

There are pictures in that thread of one iron gerotor with a stock style bypass which may help you decide.  The other has a ball valve and you can ignore that regarding your question.



Lawrenceville, GA

Hello Members  Have a quick question.  I picked up a new cast iron georotor  after market pump  many years ago. Getting ready to use it and noticed  it had no relief valve or spring in it.  Can anyone here tell me if spur gear pumps and georotor  use same valve and spring?  Have many gear pump cores but no georotors to compare. Thanks Cos