Too, many new car customers like to cruise long distances at extremely low rpm, so a tall highway cruising gear is pretty much standard equipment on most cars now. In most cases, there is a HUGE jump between the first four (or five) gears and the single, tall overdrive top gear. Too, they tend to put extremely low gearing on the lower gears, so that the car will be able to get out of its own way when it is launched. My first experience driving such a car was with a 5.0 Mustang; first gear was so deep that you had to shift before you got halfway across the intersection, yet fifth gear was so tall that you could get decent gas mileage, and cruise on the freeway at 2000 rpm or so. It was far from optimum for performance driving, but it worked okay on the street.
The stock 5.0 mustang ran a t-5 trans that had a 3.35:1 first gear and a 3.08 ring and pinion. So what that means is that with a 26” tire at 6000 rpm you could do 45mph in first gear. With SpyderMikes set up he would be able to do 50 mph in first gear at 6000rpm. So in a 3200lb car with 225hp and 300lb/ft that first gear is way to low, but in a 2300lb car with 400-500hp and 400-500lb/ft, fist gear is not low enough?
Big V8s don’t like “high” rpms, but 3000 rpm isn’t “high”. In fact, most aggressive camshafts don’t even ‘turn on’ until something above that number.
It’s not that they don’t like high rpm and I’m not saying that 3000 rpm is exactly high. My point was that for longevity (and gas mileage) it’s better to spin it slower when you are just cursing at highway speed. Having lower gears gives you more engine options as well. Spinning a 302 at 3000-3500rpm on the highway is a bit high but not really that big of a deal. But compare that to running a stroker motor like a 408. Running a 408 at 3000-3500 would be the same as running a 302 at 4000-4500 as far as the piston wear goes.
So let me qualify my earlier statements and say that IF you are primarily looking for supreme dominance on an American racetrack, or IF you bought the car principally so you could enjoy driving it on twisty mountain roads, and IF your engine is capable of spinning to, say, 6000 rpm, and IF you are equipping it with standard-height (26 inch) tires, then you would almost assuredly be better off and happier with a Pantera-spec gearing setup, i.e. 4:22 rear end, and a closer spacing of all five gears with a 2.23 1st and a 0.705 5th
If you are looking for supreme dominance on a racetrack as in a dedicated racer then wouldn’t the better coarse of action would be to put in a straight cut dog box rather then a syncro box? Another point is that 99% of the time these cars are street cars not dedicated racers, you cant race these professionally, they don’t fit in any scca class.
I guess the last point is that we can assume what would work better based on your experience racing other types of cars, or we can look at how well the originalGT40s did in real racing. Well I seem to remember them having a good string of luck back in the 60s, and I do believe they where all geared to do over 200mph and some with only 4 gears.
I’m sorry if SpyderMike took offense at what I wrote, or if anybody else thought I was being rude. I meant no offense or insult to any individual; I’m just offering a bit of a reality check about gears. When I consider a GT40, I tend to think of it strictly as a driving, performance car, i.e. an open track or backroads car.
SpyderMike posts his gearing and you post how you and Lloyd where laughing at them for those gear ratios, I don’t know why you would be surprised that people would interpret your post as rude.
Listen I have no problem with you posting your thoughts and ideas, it’s the way you went about it that got me a little agitated. You apologized so water under the bridge.
As far as considering a GT40 as a driving performance car, I agree. I put it in the same category as a Ferrari, Lamborghini, Porsche, Ford GT, Vipers, etc And I think SpiderMikes gear ratios he chose puts his car in the same category as the above cars.