John Deere 2010 timing issue

Hello,

I had written a few weeks back on a 1964-1965 John deere 2010 timing issue. I"ve ruled out a few things since then, and I am still having some timing issues, hoping someone might be able to help. I am rebuilding a 1964-1965 John deere 2010; I have no history on it, and the injection pump was just loosely installed on the block when i started working on this machine (timing was not set). I had the Roosamaster DBGVC429-2DH injection pump rebuilt, and timing mark on the pump checked. When I install the pump onto the engine, I cannot get the timing marks to align when engine is at top dead center-it is just a few degrees outside of the window of the pump, i.e. there is not enough movement allowed with the bolt/pump housing to allow for alignment. I removed the oil pump gear and moved it 1 tooth over, and then the mark way too far out of alignment the other way, so I do not think that is the issue. Does anyone have any suggestions? Is this a cam issue? Any easy way's to check if it is? One knowledgeable gentlemen in the previous post mentioned I could air time the pump if the injection pump timing mark was off, but since the pump rebuilder confirmed the pump timing...I assume i have issues elsewhere. Thanks for any help anyone can provide.

What is the timing of a 2010. You should have timing set on that. Like 12 to 20. Then marks line up.

If I recall that pump is timed end of injection like most JD pumps are, air timing the pump won't help. air timing works well on beginning of injection pumps like AC and Perkins engines. Was the pump retainer mark checked for the correct degree location per the spec sheet?

Pump retaining mark was checked by the rebuilder, and pump was also calibrated on a test stand according to the pump rebuilder (I asked this questions a few times to make sure).