3.08 or 3.76
Thread Starter
Pro
Joined: Nov 2017
Posts: 587
Likes: 49
From: Belgium
3.08 or 3.76
Hey guys,
I was looking for a 3.55 ring and pinion,pinion local guy is offering a 3.76 rear gear set.
My specs are :
355
L79 cam
11:1 compression
Afr enforcer heads
200r4 transmission, 2400 stall converter
I'm doubting between keeping the 3.08 and getting the 3.76 set.
Total first gear ratio would be 8.4 with the 3.08, 10.2 with the 3.76.
I always hear that a 10:1 ratio is perfect for performance Cars?
My issue is though that I think the gearing isn't perfect on the 200r4/3.76 combo. 75 mph cruise rpm would be 1900 vs 2350
rpm at 30 mph would be 1800 vs 2200 in 2nd.
Would the 3.08 be too long for the L79 cam? Always glad to read some more.
cheers
I was looking for a 3.55 ring and pinion,pinion local guy is offering a 3.76 rear gear set.
My specs are :
355
L79 cam
11:1 compression
Afr enforcer heads
200r4 transmission, 2400 stall converter
I'm doubting between keeping the 3.08 and getting the 3.76 set.
Total first gear ratio would be 8.4 with the 3.08, 10.2 with the 3.76.
I always hear that a 10:1 ratio is perfect for performance Cars?
My issue is though that I think the gearing isn't perfect on the 200r4/3.76 combo. 75 mph cruise rpm would be 1900 vs 2350
rpm at 30 mph would be 1800 vs 2200 in 2nd.
Would the 3.08 be too long for the L79 cam? Always glad to read some more.
cheers
Instructor
Joined: Oct 2021
Posts: 240
Likes: 82
From: Pittsburgh, Pa. da 'burg
I'm no expert on these combos by any means, but 2350 rpm at 75 mph does not sound like the motor or trans is being overworked
Also, I've read that the 3.08 is too "weak" for the 350, and is better when mated to a 427 with high torque.
FWIW
Also, I've read that the 3.08 is too "weak" for the 350, and is better when mated to a 427 with high torque.
FWIW
Race Director
Joined: Mar 2018
Posts: 10,730
Likes: 2,188
From: Golden Colorado
Be aware of who the mfg is.
US Gear, I believe, was the last ring and pinion made in USA. They are out of business now. There is some real junk out there now. All the money and work to properly set one up, you want it to last for a while.
US Gear, I believe, was the last ring and pinion made in USA. They are out of business now. There is some real junk out there now. All the money and work to properly set one up, you want it to last for a while.
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
What is your O/D ratio ? if near ..65-.75 then yu could run the .370. I am assuming you have the rear end because there are others in between that would work too. I run a 3.08 behind my 427ci small block and cruise at 80mph well bellow 2000RPM in 5th gear.
Racer
Joined: Oct 2001
Posts: 474
Likes: 64
From: Portage La Prairie Manitoba
Hey guys,
I was looking for a 3.55 ring and pinion,pinion local guy is offering a 3.76 rear gear set.
My specs are :
355
L79 cam
11:1 compression
Afr enforcer heads
200r4 transmission, 2400 stall converter
I'm doubting between keeping the 3.08 and getting the 3.76 set.
Total first gear ratio would be 8.4 with the 3.08, 10.2 with the 3.76.
I always hear that a 10:1 ratio is perfect for performance Cars?
My issue is though that I think the gearing isn't perfect on the 200r4/3.76 combo. 75 mph cruise rpm would be 1900 vs 2350
rpm at 30 mph would be 1800 vs 2200 in 2nd.
Would the 3.08 be too long for the L79 cam? Always glad to read some more.
cheers
I was looking for a 3.55 ring and pinion,pinion local guy is offering a 3.76 rear gear set.
My specs are :
355
L79 cam
11:1 compression
Afr enforcer heads
200r4 transmission, 2400 stall converter
I'm doubting between keeping the 3.08 and getting the 3.76 set.
Total first gear ratio would be 8.4 with the 3.08, 10.2 with the 3.76.
I always hear that a 10:1 ratio is perfect for performance Cars?
My issue is though that I think the gearing isn't perfect on the 200r4/3.76 combo. 75 mph cruise rpm would be 1900 vs 2350
rpm at 30 mph would be 1800 vs 2200 in 2nd.
Would the 3.08 be too long for the L79 cam? Always glad to read some more.
cheers
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Pro
Joined: Nov 2017
Posts: 587
Likes: 49
From: Belgium
Tech Contributor
Joined: Aug 1999
Posts: 15,175
Likes: 3,990
From: Connecticut, USA
FYI, there is no 376 ratio that I am aware of, there is 370 or 373.
370 NOS GM, 370 imported, 373 US Gear/Toms now only found in NOS or used.
373 is the most common ratio used with OD Trans.
370 NOS GM, 370 imported, 373 US Gear/Toms now only found in NOS or used.
373 is the most common ratio used with OD Trans.
Melting Slicks
Joined: Jun 2014
Posts: 2,236
Likes: 498
From: NJ
, there are no combinations of ring and pinion gear teeth that work out to 3.76.
Thread Starter
Pro
Joined: Nov 2017
Posts: 587
Likes: 49
From: Belgium
3.76 is a FDR for a classic mini cooper, one of my other projects 😅
Tech Contributor
Joined: Aug 1999
Posts: 15,175
Likes: 3,990
From: Connecticut, USA
Team Owner
Joined: Jul 2004
Posts: 40,412
Likes: 792
From: Redondo Beach, California
My thoughts about 3.08 and 3.73
3.08 is a great choice for a Richmond 5 speed. 5th gear is 1:1 with 1st gear being numerically large to give the torque multiplication you need with a longer duration cam shaft
3.73 is a great choice for a Tremac 5 speed. 5th gear is overdrive to give low engine rpm at freeway cruise speeds.
...............................
I've driven with both. My 69 witha L88 clone engine and 3.08 tended to bog in first gear. A Doug Nash 5 speed (now Richmond) was magic.
Love the Tremac in my 68 3.73. Nice shift. ~2000 rpm at 70 mph.
3.08 is a great choice for a Richmond 5 speed. 5th gear is 1:1 with 1st gear being numerically large to give the torque multiplication you need with a longer duration cam shaft
3.73 is a great choice for a Tremac 5 speed. 5th gear is overdrive to give low engine rpm at freeway cruise speeds.
...............................
I've driven with both. My 69 witha L88 clone engine and 3.08 tended to bog in first gear. A Doug Nash 5 speed (now Richmond) was magic.
Love the Tremac in my 68 3.73. Nice shift. ~2000 rpm at 70 mph.
Le Mans Master
Joined: May 2007
Posts: 5,028
Likes: 1,120
From: North tonawanda NY
My old stock underpowered 204hp 84 c4 had 3.07 gears stock with the 700r4.. While its true the 2004r has a higher .67 OD, when paired with a 3.55 rear its is still a stronger setup than the c4 and those worked just fine at cruising speeds. the 7004r had a lower first gear that worked better with the 3.07 gears.. the performance gear ratio for those c4s was a mere 3.36 I believe and it was rare on the 84s.
Now its also true the c4 engines were setup for more torque at actual street rpms Than many hopped up old school carbed engines with oversized cams for better WOT performance. But for an engine with a mild cam that doesnt give up such torque I cant see how this wouldnt be a good all around street combo unless theres something im missing here?
I guess it all boils down to how this combo will be used and what compromises will be made..
Drifting
Joined: Dec 2017
Posts: 1,306
Likes: 226
From: PA
Definitely move to either 3.55 or 3.70 as a good combo for spirited start and easy highway cruising in OD. I have 3.54 in my 80 coupled with a 4L60e transmission. L82 engine mostly stock, probably 260 hp net. The 4L60e has 3.06 first for a 10.8 ratio in first. It winds right up off a red light and is plenty fun for acceleration. On the upper end, 70 mph cruise is about 2,150 RPM.