Outdoor Power Equipment and Small Engines - cub cadet. 124 blows head gaskets

hi, My 124 Cub is nutorious for blowing head gaskets..
Here is a little history:
the previous owner blew one and replaced,

blew another so he replaced it and a new head.

I bought it, then I blew one,

I replaced, and checked the head and block for flatness(ok). that one blew.

I figured I didnt know what I was doing so I brought it to a repair shop. They said the sheilds were missing and the engine cant cool, they replaced gasket and assume checked for flatness and installed the shields. That one blew.

It would usually last the most of the mowing season and blow about Oct.
It has sat for 4 years now and I figured I would mess with it. I replaced the gasket again. Also plug and breather filter, and am going to adjust vavles tonite if nessesary.

What is causing it to make the gaskets blow in about 5-6 months of use? It have gone through about 5 of them. Its like the compression is to high. This is a great tractor. It will out mow the 22 HP I have. And Id like to depend on it. What, as a novice can I check to make it right. thanx alot.

You made no mention of what engine this has but I believe it is a 12 horse Kohler, model K301. You also didn't indicate if the shields were installed by the dealer you brought it to but these must be in place for the engine to cool well. Be sure, if they weren't installed, to order and install such. Next, it is extremely rare for the deck to warp since it is cast iron block. What I would be concerned with (beyond the adequate cooling by way of the shields) would be that the threads in the block are clean and therefore able to get a good torque. Run a tap down each thread hole and when reassembling use anti-seize on the bolt threads. Be sure to torque the head at 25 then 30 foot pounds.

yes the sheild were installed and a kohler 301. oops. i torqued to 35 pounds, should i loosen and retorque?