Installing Rallye Dash in a '74 duster issues

I wanna talk about the 150 speedo. As in what's the point of it? The 120 already has the graduations pretty small, so going an exact speed with the factory cable usually doing it's little dance is always tricky. The 150 makes this even trickier. Once you are in top gear, you can use the tack as a speedo. Besides, it is way cooler to say you buried the tach in top gear than to say you buried the speedo. I mean 3.55s can hit 160 at redline. I took my 150 out, and replaced it with the 120, for more accuracy. I hate speeding tickets.See up here they cost us points on our licensees, and if you get more than 5 of those blasted points, they start to cost money,a lot of money.So I save my score-card for real offenses like imprudents,lol. Yeah, I've had few of those..... Anyway that's my take on the 150 speedo.
While I'm here, I might as well talk about putting a tach in that center spot. I think it's a waste of real estate. The tach is too small and the graduations are too close together, and the factory one is extremely slow. Furthermore, it is in a bad spot. You have to take your eyes off the road to see it, and at 65 mph you are already traveling at 95 ft per second. Do you think it's a good idea to be trying to focus on that lying pos at 95fps? Well I didn't.I installed an 8000rpm, 270*, 4incher onto a bracket that I fabbed to wrap around the dashcap. When I need the tach,I slide it over to front and center. The rest of the time it is off to the right someplace. And as to that vacated center hole, I installed a factory vacuum gauge there. It may not be dead-nuts accurate, but hey who cares; it is still a very useful tool,on account of it's all relative.If it's 5% off in one place, it will be 5% off everywhere. And the 5% is very small, being less than 1 inch at 15 inches.
Yeah so that's my nickel's worth.
I like the key on the dash, but when I really nail a shift, I usually have to go looking in the back seat for my keys! I always hated looking for that column switch in the later As, especially in the dark.
Those factory gauges are notoriously slow to respond.Mine are still in there, cuz I built a reliable engine, and a reliable cooling system. So I never really look at them, and they do look nice. But the factory lighting is so poor that you can hardly see them in the dark.But the only one I need to see is the SpeedO, and I put some really bright bulbs in there,lol; Cuz, you know, I doubt the cop who pulls me over for running 5 kliks over, is gonna buy my story about me not seeing the needles on this old heap!,lol.
OK so I'm over a dime by now,TTYL

Highway patrol around here won't even bother you for 5 mph over, usually they don't even bother with 10mph over and I just drive slow on the surface streets where the speed limits are low. I do plan on doing some trackdays at some point with my car, so 150 mph is possible and I'd better get going faster than 120 or I should just hang it up. That's my take on the 150 speedo, I like 'em.

As for the tach I shift by sound, so I don't really care about the tach, but it looks better than a blank spot in the dash and is semi-useful for diagnosing rpm related issues and trying to figure out what my final gearing will be as I still have a T56 to install. Between the tach and the A/F gauge on the column carb tuning was a lot easier. I agree that the dash tach is almost useless for a shift indicator, it's too small and not particularly accurate anyway (I have an aftermarket one, they're not great). If I were drag racing and shooting for consistency I'd install a shift light somewhere like matt mentioned. Even with the tach on the dash you have to bother to look at it and process what it's reading, and if you're really hauling the mail that's a lot of real estate. The light is the way to go if you need the tach for consistency at the track.

I have considered the vacuum gauge, I actually have one for a rallye dash but like the tach I think most of the time it's just something I'm not looking at. I have one in my '71 F100 because it has a gauge cluster out of a heavy duty truck that came with one, and I don't typically pay any more attention to it than the tach (which it also has). Most of the time it's just telling me I should take my foot out of the throttle, which doesn't matter much on the F100 because it has a 390 and gets 9 mpg no matter what you do.