Which Head Gasket for SuperA with 3 1/4 Pistons?

Thanks,

Hartford

I fully realize, folks are going to respond to my post, saying, "I ran my 123+ cubic inches without a water pump for years tractor pulling." That may well be, a pull at a tractor pull lasts precisely 3 minutes, and they do it 5, 10, 15 or 20 times per year. They should try putting the tractor under load 8 to 10 hours per day, if they truly want to test their engine and ability of the cooling system.

How hard did you hit it with the sledge to brake the crank? A former neighbor hit his knee on one such swing, walked with a stiff leg rest of his life.

Even ignoring the the Rx update type variations, I have seen 5 different part numbers for the various C-113, C-123 and early C-135 engines. The differences I am aware of are the water passage size (smaller for water pump) and the size of the opening at each cylinder. The original C-113 gasket would overlap the edge of each cylinder if it was a larger bore, so a change was required for 3 1/8" bore engines. At one time, different gaskets were available for different bore engines. The only currently available numbers I could find are 366300R3 and 366301R2. Since 366300R3 is correct for a C-135, it is OK for a 3 1/4" bore with a water pump. 366301R2 is for engines with no water pump and I am guessing it is OK for a 3 1/4" bore as well.
The key to all this is the Farmall C Parts Catalog. It is the only model that had an optional water pump and it lists these 2 gaskets based on water pump or not.

If you have already installed 366300R3 and were using the same before, I would probably not go back and change it. It might become a problem if you run the tractor hard.