I see someone made up a starter link for that problem.
I can see in the pic that the pins that the throw-out bearing pivots on are not centered in the opening.
I just compared a 37 fork with a 38-46 fork and the 38-46 fork is 3/8" longer from the pivot ball to the bearing pivot pins.
The 37 fork is also 3/8" shorter from the pivot ball out to the link.
The pivot ball is also 1/4" closer to the center hole than a 38-46.
This looks like your 38-46 fork with your 37 bellhousing would move the bearing more than intended.
I know this is not an ideal setup but if you keep plenty of pedal free play you should not have the over center problem Jeff talks about.
It would be best to find a 1938-46 truck bellhousing.
