I feel confident a 4.30 rear will be great for a NA 96-01 Mustang/Cobra. These cars have low tq/hp motors, and unless you plan on power adder or a built motor gearing will be your last worry as you will likely be fighting heat. Once I looked at the gearing I knew that it had to be at least 4.10 back there. Any car achieving 70mph in second and 100+ in third with a 3.73 rear is ridiculous. I know that 5th is an over drive and has a big gap from 4th, but I feel like it would be better to grab 5th at 120mph (4.30) instead of 140 mph (3.73) to minimize the aero drag while building power in 5th and allowing 160mph to be obtainable(on Daytona).I'd be curious how this works out for you. I think A1yola was running 4.10s and he seemed to like them IIRC
For me, I'd rather not have to use 5th for the following:
- With me strapped in and my short arms, 5th is a long throw.
- Just another shift I have to make - my philosophy is the least amount of driver input results in the least amount of potential error
Also a lot of tracks will not give the opportunity for a 3400lbs 270 whp to see over 120mph. The acceleration on corner exit will be sick, the problem will be getting it to the ground.