I'm glad my response generated some amusement! I feel better already. The objective of my post was twofold:
1. To give a serious answer to the original question about what could be expected from
changing the diff ratio from 3.54 to 3.08 or 2.88 ratios. I wouldn't want Tyson, or any
other reader to expect 100mph at 3,000rpm from any ratio of differential, without
installing a 5-speed or overdrive (only practical on a +2) as well. With standard diameter
tires, a 3.07 diff should give you around 75mph at 3,000rpm.
2. To warn that if the 100mph speed was accurate, and your tire diameter is not significantly
larger than standard (which with 205/70R15 or 215/65R15 would not be the case), then
your tachometer may be seriously under-reading. This is not unusual,
though it is usually on the earlier cars with a tachogenerator that get's "tired". I know of
at least one case where an XK engine was destroyed by over-revving because the tach
was reading low. If you are confident that your speedo and tacho are accurate, then
go for it! Maybe shaving off the letters on the tires is the explanation?
Sorry to hear you have 7 feet of snow! Hope it clears up soon for you. Here in Northern California its a cloudless 73 degrees, and I'm just back from a 90 mile zip down the coast for lunch with my wife in the E. Great day for it!
