My motor is a sbc 350 with 430 horses and the transmission is a built turbo 400. i was wondering what the best rear end gear ratio would be for street and strip. I kind of like a decent top end but a neck breaking launch lol. Any advice is appreciated, thanks!

 

3.42

 

I started out with a 3.42 and it's a good all around gear. I now have a 3.89 gear and like it better but the car has turned more towards more track than street use.

 

Assuming you still have the stock 10 bolt, your gear ratio options are very limited. Using a 12 bolt or 9" will give you a lot more gear ratio options.

Best gear ratio performance depends on a lot of factors. Tire height and rpm range of the engine will determine the best gear ratio to use. For 1/4 mile performance, you want the gearing to get you to your shift point in third gear at or just before the 1/4 mile.

For street use, 3.73 gears maximum with 26" tall tires. You could go to 4.10 but you'll probably run out of rpm before the end of the 1/4 mile unless you put 28" tall tires on it. 3.73 and 4.10 gears will be fun on the street and you can still easily do highway driving but your engine rpms will be high and fuel mileage will suffer. That's why everyone wants an OD transmission.

Mid 3.xx is the best all around choice to give good enough performance on the track and good street manners.

 

If you have the stock 10 bolt then you need to upgrade to a better rear end. Putting money into the 10 bolt is a waste. You will break it.

 

Is there a direct bolt in rear end or is any aftermarket rear end going to require major modifications?

 

Moser Engineering, Strange Engineering, Mark Williams Enterprises, Quick Performance and Maybe DTS make bolt in 12 bolt, 9 inch Ford and Dana 60 rear ends for these cars.

 

Aftermarket diff is your only option for a better diff. As mentioned above, there are a lot of aftermarket bolt in choices but none of them are inexpensive. Be prepared to spend around $2500 for a complete diff. It depends which diff and options you get with it as to the final price. $2500 is a rough average.

 

Ok thanks for the help!