Slant Six 170 vs. 225

A basic turbo install doesn't have to have all that intercooler stuff. One install I did took the vehicle from a best of 23 mpg straight to a hair under 30 mpg while almost doubling the power. I was sold.
If you do the work yourself it costs less than headers-intake-carb.

My 225 gets right around 17mpg
Yeah that's about what mine gets. I don't mind the intercooler rigamoroe, I can make that look neat. It's all the other crappola that goes with it. I won't get one without it being both liquid and oil cooled, so there's more lines. Also the blow off valve and whatnot, so there's more stuff. It's just too much crammed in the small space of an early A body engine bay, IMO. If I thought I could do it and keep it neat, I probably would. All that said though, I'm having an absolute blast with it naturally aspirated.