Valve/Spring installed height: On a completely stock Model T engine this would be easy to figure out. At the low RPM's a T runs in stock form the goal of setting up a rebuilt T to this spec may be less important than on an 05 Mustang.....But I have redone my block with new valves and they are not reproduction T valves so I want to set them up close and because the keeper groove is in a different spot I'll need to change a few things. The law of unintended consequence, change one thing, now you have to change two more.
The biggest - hardest part is because when you grind the seat and the face of the valve it sits lower, and thus reduces the pressure the spring holds the valve close.
If I can figure out a close ( around to the closest 1/64" ) measurement I can take a new spring, compress it to installed height and find that pressure, and adjust my "new" non stock set-up to keep this spec in line.
The last two things I do not have my engine close by at the moment, and am hoping to have help here to find the answer from someone who has a close to stock setup at hand.
Here is photo from cut-away motor, with compressed length, as installed with stock valve, pin, and retention cup.
A T valve spring tests at 24-28 lbs @ height compressed to 2 1/8"
Perfect Dan, thanks. J