yes, all internals. its a very popular thing to improve your old ford. in 39 ford changed the design of the syncro's to basically the same thing you find in a modern car. what you look for is a 40-48 side shift trans (3 on the tree), and put all the guts out of that case into your top shift case. you would also want the double detent 81a style cover, which your 37 shift lever will fit. these tranys are common, craigslist, swap meets etc. but be sure to pull the cover off, look for the 28 tooth cluster, and condition of the rest. heres a link to mac vanpelts wonderful web site to further explain the "39" style trans
http://www.vanpeltsales.com/FH_web/f...sID_3speed.htm theres lots look at there, go to "home" and check other stuff too