Rearend swap??

[duppyconqueror]

Yea my mechanic recommended 3.73's. I don't know if it makes a difference but I usually cruise a bit slow on the interstate like 60mph or so.

 

[DRIVEN]

I like to drop this link all over the place. http://www.angelfire.com/fl/procrastination/rear.html It's a pretty helpful calculator and I've found it extremely useful over the years. Plug your specs in and see what you come up with.

 

[duppyconqueror]

thanks that's a nifty tool. What is a good rpm value to cruise on the highway? maybe 2500?

 

[DRIVEN]

Totally up to you. Some guys like to practically idle down the freeway and can almost get away with it if they have a torquey big block. Other guys gear strictly based on trap rpm at the track. For a street car 2500 is probably a pretty good target for a lot of people though.

 

[drogg1]

Just if anyone's curious, finding engine RPM, transmission gear ratio, rear gear ratio, and MPH isn't too tough. It just involves conversion of units essentially. Here are the four equations:

RPM = (336 x (Trans Gear Ratio) x (Rear Gear Ratio) x (MPH))/(Tire Diameter in Inches)

Trans Gear Ratio = ((RPM) x (Tire Diameter in Inches))/(336 x (Rear Gear Ratio) x (MPH))

Rear Gear Ratio = ((RPM) x (Tire Diameter in Inches))/(336 x (Trans Gear Ratio) x (MPH))

MPH = ((RPM) x (Tire Diameter in Inches))/(336 x (Trans Gear Ratio) x (Rear Gear Ratio))

This is, of course, for ideal conditions with no slip or play anywhere in the driveline. It still is accurate enough to get close to where you want to be.