You could try a different route...
My daughter likes '49-'51 Fords which are pretty close in size to your Chevy. In a couple years, I'll start a father/daughter project car, and it will likely be one of these Fords. I had what I thought was a unique way to easily modernize one... but upon some research, it turns out it's pretty common: Swap the entire frame for a S10 frame.
Most seem to keep the frame and suspension but then put in some other engine. I was thinking of keeping the EFI 4 banger and manual tranny. Old car with modern, easy to replace parts underneath that should be reliable to drive around. I'd bet 30+mpg would be easily achievable.
Here's a video of one guy doing this on a budget. He uses a carbureted 4.3V6 and claims 22mpg:
(I wouldn't recommend replicating the frame notch though)