I have 1938 Ford and I have located a y-block engine.  What would be involved in installing the y-block and hooking it up to the '38 tranny?

There's an adapter on EBAY now at:

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

I had a 41 Ford Coupe I put a 55 t-bird 292 in years ago. To get the engine in, going back to front ,you need the trans adapter, t-bird or truck oil pan, t-bird timing case cover,, motor mounts that bolt to the timing case, 39/49 rubber motor mounts. I don't remember if you need a droped tie rod.
To get it running is even more parts, but it's a great combo, and runs and drives really nice. 
I saved myself a lot of problems and kept it 6 volts, used a t-bird geneator mount. 
 I had my 41 8 years and put over 50,000 miles on it.I  

While you may be able to adapt the '38 transmission to the Y block and it will work, it will not stand up to any abuse. I would think about using a more modern and tougher transmission. 5 speed would be my choice for a hot rod.

Don't know if it will help, but this ad on Craigslist has an adapter for a later flathead conversion.

"The Master Cylinder"

Enjoying life at the beach in SOCAL