Rear Gear too High...Suggestions for New Ratio

[kryptik]

Hello Guys,

I am using a Currie 9" Unit with 3.50:1 Gears, Tru-Trac, and 31-spline Axles. This was originally set up for an automatic transmission (.70 OD) 68 Camaro. Since that car is now gone (RIP) I have modified and installed this axle into my 1970 Camaro.

The problem I am having is that when getting into first gear, I have to slip the clutch a little too much for my liking. The motor is tuned properly, the timing is set, no issues there. Also, when in 5th on the highway, I have to be moving AT LEAST 68mph (already post-legal speeds ) to keep the RPM's up and the motor happy. The RPM's are right around 2100-2200 at 75mph...too low.

I am really considering swapping out the 3.50:1 gears to either 3.89:1 gears (roughly 200-220 RPM increase @2000) or 4.11:1 gears (roughly 350 RPM increase @2000). I just wanted to hear what y'all would recommend and any other suggestions you may have.

Some quick specs on the car:
'70 Camaro ~3100-3200lbs
GMPP zz383 Long-Block
222/230 @.050 | .509 intake / .528 exhaust lift cam
Fastburn 62cc Heads
Edelbrock RPM Air Gap
Quickfuel 680cfm SS Vacuum Secondary
Tri-Y 1-5/8 Headers into 2.5" x-pipe
TKO600
2.87:1 first gear
0.64:1 OD



Any help will be much appreciated

Cheers,
Matt