22-inch Replacement Rad. for six cyl.?

All good info. Fans are only effective at low vehicle speeds - est. under 40 mph. It is those hot days and climbing uphill and even over 60 mph that get the gauge moving up. Yes, core may well be partially restricted, but our only rad shop very expensive - est $450. to $500. for a 19 inch re and re. New unit ordered online will be cheaper. One more question would be if the 19-inch. core available as a 'high-density' version (with more tubes fitted closer together) - as the 22's are available?
I'll do some searching as suggested. thanks.