Pony popped a valve guide keeper

Hi SS,
MMmm, can only think that the engine sat with that valve in the open position and the guide and valve seized/stuck together during the time of inaction.
When you tried to start the engine if the guide was loose enough in the block, compression could push the valve and guide back when the follower cam off the cam lobe allowing the retainer to turn and come out of its groove.
Cheers,
Eddie B.

Are the guides a press fit in the block?
This guide seemed to move without much difficulty.
Could try a new one I guess if you think I should.
Regards Chris

Read many many pages about pony engines and it seems that the valve guide (bushing) does just slide in.
So feeling okay about things I re assembled the pony and filled up the coolant. Started it and runs fine. Easily starte the main engine now.
All said its not a hard thing to work on. Some parts are a little heavy but managable.
Regards Chris