KRAIG - Same thing here on my CC's. No REALLY hot exh. manifolds. The straight pipe I put on the K321 was aluminized steel. Normally pretty heat resistant, and I even had SON TIG weld it to the flange to bolt to the exh. port. Except for a little rust right around the weld it doesn't show much heat "Distress" even after 150 hrs of running. But then knocking the tops off a little bit of crabgrass & a few dandelions in the yard last summer wasn't a real BIG load with a 38" deck.
Did You read the article Gerry posted in my IH Ramblings O/T thread from the other day? Farmall Super M with M&W pistons would heat up not only the exh. manifold but the 2" dia black iron pipe and bottom of the muffler on an SM pulling hard after several hours. And people wonder why they can't find an M/SM/400/450 cyl. head that isn't cracked around the exh. ports anymore!?!?!?
Did You read the article Gerry posted in my IH Ramblings O/T thread from the other day? Farmall Super M with M&W pistons would heat up not only the exh. manifold but the 2" dia black iron pipe and bottom of the muffler on an SM pulling hard after several hours. And people wonder why they can't find an M/SM/400/450 cyl. head that isn't cracked around the exh. ports anymore!?!?!?