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Vehicle Information: Model: 911T; Year: 1972; Body Type: Targa; Engine (type, size, modifications): 6 cylinder, 2.4L, Carrera chain tensioners, Turbo lower valve covers; Total Mileage: 100K;

Hi Ed -I am considering an upgrade for my 2.4L "T" engine. I want to use 2.2L "S" pistons along with an "S" camshaft for my model to increase the compression ratio. After talking to some shops and parts companies I am wondering whether to buy 85mm pistons and machine my original cylinders or keep the spec 84mm size. From what I'm told the idea is that if I go to 85mm I will be sure of the fitting and size where as if I go with 84mm pistons and use my original cylinders I could get some knocking due to the wear and tear on my original cylinders. I have not yet had the cylinder specs checked on my engine so I don't know how much wear might be evident. What do you think I should do between the following options:1) Get 84mm pistons and keep original cylinders.2) Get 85mm pistons and have original cylinders bored.3) Get an 85mm piston and cylinder set.Thanks for your help Ed,Sanford

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