How much gear for the 1/8 mile

Quote:

---

I am wondering how much gear I should be running
for the 1/8 mile. Currently I have 3.91's
I shift from second to third at the
1/8 mile. 6000 rpm's. 8.3 at 85mph.
The car is street driven/ not highway.

1973 Dodge Dart Sport
360
X heads
solid cam
727 manual valve body
3500 stall
drag radials 325/60/15's

thanks for input.

Matt

---

Quote:

---

I am wondering how much gear I should be running
for the 1/8 mile. Currently I have 3.91's
I shift from second to third at the
1/8 mile. 6000 rpm's. 8.3 at 85mph.
The car is street driven/ not highway.

---

Matt, unless you have a spare rear end center section setup with the new gears to swap out for street vs track, don't gear the car for 1/8 mile when it is a street car. I wouldn't even gear it for 1/8 mile if it was a race car unless it was something special, race gear it for 1/4 mile so you don't have to say "I can't run 1/4 mile my car is geared for 1/8"

That being said, if the mph at the 1/8 mark is the same, the gear change in a 727 from 2nd to 3rd is 1.45. So to cross the line in 3rd at the same rpm and mph as 2nd:

3.91 x 1.45 = 5.67

Now if you pick up some mph, say from 85 to 90, then use:

5.67 x 85/90 = 5.35