Ken - National chains such as AutoZone, O'Reillys's, NAPA, and Advance/PartsOne have web sites where you can ask about parts. They all have listings (although limited) back to 1944. I suspect the software & database are related on all these sites. If they don't have a listing for Kaiser or Frazer with a 226 engine, look for 54-61 Willys station wagons.
After seeing your request, I went to AutoZone and asked for a fuel pump for a 1950 Studebaker Champion. It showed only 1 electric fuel pump Airtex Master E8011 and I wasn't happy with the price. 2 years ago when I did such an inquiry, there were 4 part numbers (there are several different yet popular electric fuel pump designs). All of these worked on 6V and polarity (- or + ground) wasn't a problem.
If you find a fuel pump available at one of these national chains, you can try going to the manufacturer's site and see if they have more specifications which in your case would be the rated psi.