I wish I had the '39 For Tudor Delux, that my dad bought new, but, it was wrecked in '56 (not bad, rt front fender and grill) but he didn't fix it and in '60 he had it hauled off for junk.
Afrter WWII he worked as a mechanic at Meyer & Welch, a Ford rebuilder and owner of the Novi, Indy Car. My first car was a '48 Merc coupe, that I wasn't to drive until I got my license, couldn't resist and he haul that off for junk but I got to keep the eng & '39 trans. It was bored 3/16.
You probably have the "Helmet" type dist (3 bolt) A good up grade for that, is the later crab dist but, it's 2 bolt, you can get a adapter or change the timing cover. It's easier to work on, too.
Also, you can keep your full floating rods, if you offset grind the Merc crank, to 4 1/8, for the needed 2" journals. You'll need custom pistons for that though at the smaller bore.
Another thing you can do, is put SBC exhaust valves in it, both for the In & ex. It doesn't gain to much, but they are cheaper. A very good valve job, will help it. If you do your own valve job, I can give you a Black & Decker type pilot I might even have a Sioux.
You'll probably spend a lot of time at Speedway Motors
I'd like to see a project thread, too.