1972 k5 Blazer hitch

[1972MaineK5]

Good morning. I've read some old posts regarding a hitch for a 1972 k5 blazer. Some decent input and I've ALMOST pulled the trigger and ordered one. Lots of measuring and lots of attempting to get schematics from manufacturers. However, I thought I'd put it out there and see if anyone has actually ordered one recentry and if so maybe a brand and part number? Ideally I'd like a class 4. The threes are a little light for my purpose. I pull a boat which maxes out at about 6000lbs. Yes I know I'm pushing what I can comfortably tow behind the blazer but, I only need to tow it twice a year abut 5 miles each way maxing out at about 40 mph. Once to put it in in the spring and once to pull it out in the fall. Oh, and I'd like the receiver to sit just below the license plate. Standard bumper. Thanks for any input and help.