Question about gearing for Top Speed

harrisonm said
I have a question about gearing your car for top speed. I mean like Bonneville Salt Flats top speed. Let’s say you have a 69 340 barracuda and at 6000 RPM you are at 120 miles an hour with 3.55 gears. And let’s say that same 6000 RPM would give you 140 miles an hour with 3.23 years, and 160 miles an hour with 2.76 gears (all theoretical-i know there are charts available online that give speed for given RPR/tire size and ratios). I know there is a point at which continuing to increase the overdrive gear ratio will actually start to slow you down. I assume the ratio will get to the point where the engine’s torque and HP will start lo lag. At some point, to go faster, you are going to need more horsepower not just more overdrive gear ratio. I just wonder if anybody knows where that is. I am guessing it would probably be somewhere around a 1:1 ratio rear axle

As someone whom has foolishly driven his Mopar in excess of 160, -get a longer, wider, heavier car. I may get beat up on the A body forum, but for YOUR safety I'll risk my reputation. Besides HIGH-END Brakes, a driveshaft safety loop, internally balanced engine, rebuilt differential, new wheel bearings-overpacked with grease,, Z rated tires, new,, an aerodynamic vehicle, with low-body weight and a roll cage...

...at any rate high speed steering corrections with a short wheel base are too often followed by lethal loss of control. I feel a B-body would be better for top speed, but you need to spend more on safety than a plan of high horsepower engine, gears, and brakes.

In my humble opinion, though the physics promotes narrow wheels for speed, I recommend wide wheels for control as well.