My advice would be to seek out the parts either from a donor truck, salvage yard or a member on the forum. $800 is way to much, IMO. I did it to my '70 many moons ago. It's well worth it. I finally had to install a rebuilt gear box, today in fact, that I purchased from Advance Auto. They have them very reasonable right now. They're only $139+$45 core charge. At the moment you can get 15% off plus $50 towards your next purchase of $100 or more. That could go towards a pump.
Here's a link.