You fergot the most important option, Dave....
#6: Buy a Corvette that already HAS the 140mph speedo.
My vote is #6....
Rodger has a pretty good rep among the older Corvette community for doing good work. Even so, recalibrating your speedo and changing the faceplate might work right from the start, or it MAY need to be sent back for further fine-tuning....ya never know. If I had to make a choice for meself, I'd go with one from Rodger.
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Joel Adams
C3VR Lifetime Member #56
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"