Tony - the large 260 tach is a direct swap for the large 240 tach on the older model cars (80's) - not sure about the newer cars. You don't have to send it out to have it calibrated. Simply hook up a shop tach under the hood, and jumper the 260 tach so it's connected to the engine while out of the dash. At different rev points, you simply turn a small screw (potentiometer) on the back of the 260 tach to calibrate it to the V8. The 4 cyl. tachs have the same adjustable feature, but not enough range to deal with the V8. I bought my tach from someone on the boards who had a Bertone that they had swapped the V6 out for a turbo 4 -- they put a 4 cyl. tach in theirs, and sold me the 6 cylinder tach for a very reasonable fee. Looks completely factory, and with the car on the dyno -- when the DynoJet was showing 5300 rpm, I was showing 5400. Not too bad....
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82 242 5.0L; 97 318ti; 06 WRX wagon