What Rear-end ratio ?
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Joined: Mar 2018
Posts: 66
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From: Davenport Iowa
Thank you all for your help. I went ahead and spent the money for 3:55 gears. After putting in some time on the road, my decision to change them had nothing to do with highway RPM's, but rather the constant urge wanting it to shift one more gear! It was driving me crazy, as I am used to a manual 4 speed. I do a lot of 35-50 mph so after much deliberation, I had them swapped. I wanted to retain as much bottom end as I could so just went with the 3:55 instead of the 3:36. Years ago I have a 66 GTO with about the same HP that had 3:36 in it so I knew what I might expect from that ratio.
Looking back, do I think I made the right decision?? ABSOLUTELY!! It's much nicer to drive. As for the highway, I live by both interstate 20 and a couple state highways, but I never really have the occasion to get on the interstate, and it feels much better to drive at a posted 65 mph on the state.
I have been an avid firearms collector for 40 years so I just sold a couple to pay for the switch.
All's well that ends well!
Oh and 76strokervette, it did have series 3 carrier! fyi
Thank again
Looking back, do I think I made the right decision?? ABSOLUTELY!! It's much nicer to drive. As for the highway, I live by both interstate 20 and a couple state highways, but I never really have the occasion to get on the interstate, and it feels much better to drive at a posted 65 mph on the state.
I have been an avid firearms collector for 40 years so I just sold a couple to pay for the switch.
All's well that ends well!
Oh and 76strokervette, it did have series 3 carrier! fyi
Thank again
Last edited by John Swift; Jun 6, 2018 at 09:57 PM.
Le Mans Master
Joined: Jan 2001
Posts: 6,743
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Glad you're happy. I have 4.11s and I put in a 0.62 OD tranny many moons ago.
Here's a gear ratio vs tire size vs rpm vs mph calculator. Just FYI.
http://www.crawlpedia.com/rpm_gear_calculator.htm
Here's a gear ratio vs tire size vs rpm vs mph calculator. Just FYI.
http://www.crawlpedia.com/rpm_gear_calculator.htm
Thank you all for your help. I went ahead and spent the money for 3:55 gears. After putting in some time on the road, my decision to change them had nothing to do with highway RPM's, but rather the constant urge wanting it to shift one more gear! It was driving me crazy, as I am used to a manual 4 speed. I do a lot of 35-50 mph so after much deliberation, I had them swapped. I wanted to retain as much bottom end as I could so just went with the 3:55 instead of the 3:36. Years ago I have a 66 GTO with about the same HP that had 3:36 in it so I knew what I might expect from that ratio.
Looking back, do I think I made the right decision?? ABSOLUTELY!! It's much nicer to drive. As for the highway, I live by both interstate 20 and a couple state highways, but I never really have the occasion to get on the interstate, and it feels much better to drive at a posted 65 mph on the state.
I have been an avid firearms collector for 40 years so I just sold a couple to pay for the switch.
All's well that ends well!
Oh and 76strokervette, it did have series 3 carrier! fyi
Thank again
Looking back, do I think I made the right decision?? ABSOLUTELY!! It's much nicer to drive. As for the highway, I live by both interstate 20 and a couple state highways, but I never really have the occasion to get on the interstate, and it feels much better to drive at a posted 65 mph on the state.
I have been an avid firearms collector for 40 years so I just sold a couple to pay for the switch.
All's well that ends well!
Oh and 76strokervette, it did have series 3 carrier! fyi
Thank again
Last edited by carriljc; Jun 6, 2018 at 10:46 PM.
Thread Starter
Advanced
Joined: Mar 2018
Posts: 66
Likes: 1
From: Davenport Iowa
Glad you're happy. I have 4.11s and I put in a 0.62 OD tranny many moons ago.
Here's a gear ratio vs tire size vs rpm vs mph calculator. Just FYI.
http://www.crawlpedia.com/rpm_gear_calculator.htm
Here's a gear ratio vs tire size vs rpm vs mph calculator. Just FYI.
http://www.crawlpedia.com/rpm_gear_calculator.htm
I actually used this through this whole thread, and project.. .http://tri-5.chevyrides.com/rpm.php
My funds didn't give me the luxury of swapping the tranny. The cost was well over twice as much, or otherwise
I would have done it.!
Race Director
Joined: Mar 2016
Posts: 14,406
Likes: 8,212
From: Napa Valley California
Thank you carriljc
I actually used this through this whole thread, and project.. .http://tri-5.chevyrides.com/rpm.php
My funds didn't give me the luxury of swapping the tranny. The cost was well over twice as much, or otherwise
I would have done it.!
I actually used this through this whole thread, and project.. .http://tri-5.chevyrides.com/rpm.php
My funds didn't give me the luxury of swapping the tranny. The cost was well over twice as much, or otherwise
I would have done it.!
Race Director
Joined: Oct 2008
Posts: 19,230
Likes: 1,672
From: Long Island
My 67 has 3:70 and is not pleasant on the highway, my 72 has 3:36 and is more comfortable on the highway.
My 71 has a roller motor and 3:55, but has a 5 speed with a .6 overdrive - the best of both worlds. (400 hp)
My friends 70 has 3:08 and a turbo 400 -stock like my 67 (4 speed) and 72 (auto) it's really nice on the highway.
My 71 has a roller motor and 3:55, but has a 5 speed with a .6 overdrive - the best of both worlds. (400 hp)
My friends 70 has 3:08 and a turbo 400 -stock like my 67 (4 speed) and 72 (auto) it's really nice on the highway.
