Trans ratios???

art leong · 11-16-2008, 07:56 PM

I'ts been a long time since I've had any options at all relating to transmission ratios. Back in the late 70's we had the first ever lower gear planetary set for a 727 torqueflite. In our B/SA Hemi Challenger. At the time we didn't see any difference. Didn't change anything else just the planetary gear.
Now I have an oportunity to get a lower first gear 2.84 (now 2.69) second gear is close to the same as I'm running now 1.57 (now 1.55) third is 1 to 1 on both but the lower gear tranny has an overdrive 4th gear 0.88.
Both are automatics.
The final drive ratio on the 4 speed is 4.10 to 1 (now 3.72 to 1)
I figure I can run a taller tire with the 4 speed.
This science is completely new to me.
What is the general thought here?
I'm running a basicilly low torque motor 151 cu inches in a fairly heavy car 2600#

11-16-2008, 07:56 PM	#1
art leong VIP Member Join Date: Dec 2001 Location: Richmond Hill, Georgia Posts: 2,003 Likes: 0 Liked 1 Time in 1 Post	Trans ratios??? I'ts been a long time since I've had any options at all relating to transmission ratios. Back in the late 70's we had the first ever lower gear planetary set for a 727 torqueflite. In our B/SA Hemi Challenger. At the time we didn't see any difference. Didn't change anything else just the planetary gear. Now I have an oportunity to get a lower first gear 2.84 (now 2.69) second gear is close to the same as I'm running now 1.57 (now 1.55) third is 1 to 1 on both but the lower gear tranny has an overdrive 4th gear 0.88. Both are automatics. The final drive ratio on the 4 speed is 4.10 to 1 (now 3.72 to 1) I figure I can run a taller tire with the 4 speed. This science is completely new to me. What is the general thought here? I'm running a basicilly low torque motor 151 cu inches in a fairly heavy car 2600# __________________ Art Leong 2095 SS Last edited by art leong; 11-16-2008 at 08:00 PM.