Old blue - I'm doing the same thing to my '39. Look for a 83 - 87 S10 or astro van trans preferably with a 4.3 v6 in front of it. The 2.8 V6 and 4 cyl had a very low 1st gear and too high of an OD. I'm using a 86 astro van with a 3.5 1st and a .73 OD. With the astro you can also utilize the clutch assy.