I'm comfortable with the revs, too, but wanted to be able to get all the way through a largish intersection without having to shift while still somewhere in it. I started with a 4.08 in mine, as many of us do. A little math showed me that, starting from that ratio, the original ratios for european 113s -- 3.92 and 3.69 -- would only drop my revs by about 5% and 10%, respectively. The same calculation for the 3.27 yields very close to a 20% result. I drove smaller, higher-winding engines back in my youth and so don't miss the comfort that 2,000 rpm cruising gives to guys with the much more common V8 history, and the five and ten per cent gains didn't seem worth the time, expense and effort, so when I discovered that there was such a thing as a 3.46 ratio, I guessed that it would be the best to get me where I want to be ... and it sure is. 3.46 represents a 15% reduction in revs from the 4.08, which feels about right to my metallic partner and me. Yes, we do spend a lot of time in 3rd and below, just as we spend most of our time either in traffic or on the rolling, snakey blacktop where I'm not nearly skilled (or crazy) enough to have much need for fourth. When it does come time for five or six hundred miles of cruise to PUB, for instance, we're still around 4,000 and happy, eating up the miles. The pipes come into a really nice resonance around 3800-3900, too, don't they. ;~)
Downside: I was diligent and fortunate to find a nice 3.46 axle, Joe went through it and installed it beautifully, and it's great. BUT... I lost the 'Differential Vent Vomit' lottery. Some significant minority of swaps will not tolerate the removal of the external circulating tube without blowing all their lubricant out though the vent at the top of the center differential ring gear housing. That large U-shaped tube conflicts with the understructure of 113s, where there's less room than under the donor sedans. Removal is easy and neat. Most axles tolerate the U-tube-ectomy but those that do not make for a messy surprise and a serious risk to the health of the axle. It can be altered sufficiently to clear the understructure but that is much better done prior to installation, and it's tricky trying to predict just where and how to tweak it when it's out and clear of the car where it's most easily got at. Altogether an inconvenient situation, one which I cannot seem to solve myself nor have I gained any effective enlightenment from those much more experienced in such matters, several of whom I've polled thus far. Most unsatisfactory. ;~(
I continue in surprise and disappointment that this august body tolerates our inability to diagnose, predict and prevent these occurrences. Is a puzzlement. [Yul Brynner, King and I, 19...54? ah, i dunno]
Happy motoring all,
Denny