Brian Moore, I agree, the thermostat works on six and v8 engines.It would be used on aluminum thermostat housings also the swivel neck. I think the vendor puts both gaskets so as to cover both applications. I suspect maybe the cost a little more? If you were to buy the thermostat only $8.50 and a $1.00 flat gasket As it probably wouldn't be much more of a difference in cost including the o ring.


http://i1305.photobucket.com/albums/s554/icecreamman55/0710ct_15_zchevy_350_engine_zpsvix59j23.jpg[/IMG]


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Steve