Okay, I swapped my spur hammer for a bobbed 3914 hammer in my 439/639 hybrid. My decocker no longer functions, but everything else is fine. Luckily I have a spare sear release lever, I put it in and the decocker now functions as intended but the lever is so high in the frame that the slide barely clears it Now for my questions, why does a hammer replacement change the position of the sear release lever and since the new lever rides so high in the frame so some fitting is in order, but where do I begin this process, as always any advice/input is appreciated.

If the new hammer has even slightly deeper sear notches, it will require more travel for the sear release lever to push the sear out of engagement with the hammer.

Sear release levers are adjusted by carefully stoning or filing the angled "foot" on the bottom that pushes on the sear.
If you lay your old sear release lever on top of your new sear release lever, you should be able to see that that foot on your new lever is slightly longer.
Properly adjusted, your new sear foot should have a small amount of material removed but still be longer than your old sear foot.

Does this all make sense?

John

This makes perfect sense, I did compare the two levers and that is exactly what i have, I'm probably going to stone a bit from the new lever, until the slide fits without inference and call it a day. Interestingly enough the "foot" angles aren't consistent between them though, I thought they would be. I remember some very good info from our member BMCM on checking with pin gauges for proper operation of the decocker, I may have to do some thread searches.

On new manufactured sear release levers, the foot angles are consistent.
The angle is sometimes inadvertently changed during the filing.

John