Originally Posted by TrueWildMan
How do you check which PCM you have? And what do you mean by a "drilled" t-stat? And how do you measure the SC pulley?
Are you wondering if you're chipped? It depends on what type it may be. You'll have to pull your PCM (above the passenger footwell/hush panel, the silver box). If it'* aftermarket, you'll see Superchips, Jet, ASE, or something under the little 2-screw cover for the PROM. The Jet is typically a piggyback, and the Superchip is typically a replacment prom. If you don't see any of these, it'* probably stock.
Most aftermarket chips remove the top speed limiter. I'm not suggesting you test the 128-130 cutoff, but if you've been that fast, you would know. Getting the PCM out can be a bitch, but it'll answer alot of questions. You may also check your redline rev limiter and see if that'* raised from stock.
The drilled 180° thermostat prevents the initial drivetrain 'heat satuaration'. You can still spike higher than 180, but it takes longer. It'* a much better option than the 160, unless you're running a PCM that allows for it. My Jet stage 2 chip was tuned for the 180, and was a requirement (as well as intake and exhaust) before using the chip. The number and size of the holes you drill in the thermostat depends on your summer/winter temps, and whether you want to change thermostats twice a year. You get as hot as I do in the summer, but you get colder in the winter. I wouldn't drill more than (2) 1/16" diameter holes unless you want to change back in the winter. You just drill the holes on the flat portion of the thermostat where the rubber seal won't block them, and make sure you de-burr well and rinse it before re-installing it.
The climate differences are the main reason I don't suggest buying a pre-drilled thermostat from one of the GP parts sources.