The high volume pumps have longer rotors, so the body would be longer. Call melting they will tell you the dimension. I agree to much in pan, I hate to say it but it looks like a tear down keep checking it up to you to replace bearings and button it up and fire it up see how it idles
oil pump at 4k rpms is 8 gpm , if high volume so in on minute your
oil is filtered, on second thought pull engine and disassemble it over