"Would a KKM intake and custom exhaust stress this high mileage motor to the point of failure? That is, will a freed-up intake and exhaust make it impossible not to bang off the rev limiter? My goal is to get 100,000 miles out of the stock motor; however, are the gorgeous engine sounds too much to resist?"
Yes, the sound will be impossible to resist! With the KKM & Bassini, the sound is glorious @ 7000RPMs. But this should not hurt the motor. The Duratec is built to rev with a trick lightweight, low friction valvetrain (hollow cams, roller figer followers - just now showing up on the new M3). Fuel cutoff @ 7000 RPM is conservative, engine longevity OK @ 7500RPM and the racers have run stock valvetrain (except big valves) to 8000RPMs reliably. Beyond that is looking for trouble without valvetrain work +/- forged rods. I think intake filters and exhaust mods are all ok longevity wise Chips, UDPs - thats another story..
Let her REV!
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Dan
99SVT - Tropic Green
#554/2760
Stock - except minor intake, exhaust, & motor mount enhancements
