355 or 345 gears
Thread Starter
Launching!
Joined: Apr 2019
Posts: 206
Likes: 11
From: Bay area
355 or 345 gears Hey guys so I have a 95 trans am w/ an a4 and been pulling my brain apart trying to figure out which gear ratio to get.
Lt1 mods:
Volant cold air intake
Granatelli maf
58mm Holley throttle body
Edelbrock intake manifold
Compcam 1.6RR
Compcam 502 cam
Speed engineer LT Headers
Speed engineer true duel exhaust /xpipe
Solomon tune
What gears will go well with these mods while also having some decent gas mileage. I heard the 355s will give bad gas mileage then the 345s. The rear is stock (273s) w/ some meaty nittos (18/285/40s) I'm planning on slapping on an 3600 hi stall on soon after. But since my pinion is leaking I'm just going to get this out the way and replace it with better gears
Lt1 mods:
Volant cold air intake
Granatelli maf
58mm Holley throttle body
Edelbrock intake manifold
Compcam 1.6RR
Compcam 502 cam
Speed engineer LT Headers
Speed engineer true duel exhaust /xpipe
Solomon tune
What gears will go well with these mods while also having some decent gas mileage. I heard the 355s will give bad gas mileage then the 345s. The rear is stock (273s) w/ some meaty nittos (18/285/40s) I'm planning on slapping on an 3600 hi stall on soon after. But since my pinion is leaking I'm just going to get this out the way and replace it with better gears
Last edited by LT1DG; Apr 28, 2025 at 11:37 AM.
Find a rear end from a six speed car which should be 3.42, that would be a cheap and nice upgrade.
if you are going to swap gears, 3.73 is a nice sweet spot for the 4 speed auto.
if you are going to swap gears, 3.73 is a nice sweet spot for the 4 speed auto.
Hey guys so I have a 95 trans am w/ an a4 and been pulling my brain apart trying to figure out which gear ratio to get.
Lt1 mods:
Volant cold air intake
Granatelli maf
58mm Holley throttle body
Edelbrock intake manifold
Compcam 1.6RR
Compcam 502 cam
Speed engineer LT Headers
Speed engineer true duel exhaust /xpipe
Solomon tune
What gears will go well with these mods while also having some decent gas mileage. I heard the 355s will give bad gas mileage then the 345s. The rear is stock (273s) w/ some meaty nittos (18/285/40s) I'm planning on slapping on an 3600 hi stall on soon after. But since my pinion is leak I'm just going to get this out the way and replace it with better gears
Lt1 mods:
Volant cold air intake
Granatelli maf
58mm Holley throttle body
Edelbrock intake manifold
Compcam 1.6RR
Compcam 502 cam
Speed engineer LT Headers
Speed engineer true duel exhaust /xpipe
Solomon tune
What gears will go well with these mods while also having some decent gas mileage. I heard the 355s will give bad gas mileage then the 345s. The rear is stock (273s) w/ some meaty nittos (18/285/40s) I'm planning on slapping on an 3600 hi stall on soon after. But since my pinion is leak I'm just going to get this out the way and replace it with better gears
Thread Starter
Launching!
Joined: Apr 2019
Posts: 206
Likes: 11
From: Bay area
I found one around my area but I want an brand new unit. Just a Peace of mind lol.
I'm Leaning more towards the 3.55 just cause it right in the middle. But haven't gotten any information on anybody experience with it.
That's nonsense. Just because an engine may operate at a higher consistent RPM does not mean it will burn more fuel. What "kills" fuel efficiency is load on the engine.
Last edited by SS RRR; Apr 26, 2025 at 08:38 AM.
TECH Veteran
Joined: Dec 2008
Posts: 4,145
Likes: 61
From: Little Rock, AR
I read the 3.73s are fun as hell. But kills gas mileage and ppl don't like highway drives.
I found one around my area but I want an brand new unit. Just a Peace of mind lol.
I'm Leaning more towards the 3.55 just cause it right in the middle. But haven't gotten any information on anybody experience with it.
I found one around my area but I want an brand new unit. Just a Peace of mind lol.
I'm Leaning more towards the 3.55 just cause it right in the middle. But haven't gotten any information on anybody experience with it.
Thread Starter
Launching!
Joined: Apr 2019
Posts: 206
Likes: 11
From: Bay area
Thread Starter
Launching!
Joined: Apr 2019
Posts: 206
Likes: 11
From: Bay area
https://www.rigidaxle.com/products/1982-1998-gm-7-5-10-bolt-chevy-ring-and-pinion-gear-set-w-master-bearing-kit?variant=36139100733602
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Thread Starter
Launching!
Joined: Apr 2019
Posts: 206
Likes: 11
From: Bay area
Thread Starter
Launching!
Joined: Apr 2019
Posts: 206
Likes: 11
From: Bay area
TECH Fanatic
Joined: Jun 2007
Posts: 1,255
Likes: 11
From: centerville, ohio
I run a 3.54 power lock in my Jag along with a Yank SS3600 stall and it seems perfect to me. It'll run 70-80 on the highway if you want and have pulled a 1.74 60' at the track. I don't think about mileage because it's hard not to flash the convertor for the fun factor. It's also been in car for 20 years.
Thread Starter
Launching!
Joined: Apr 2019
Posts: 206
Likes: 11
From: Bay area
I run a 3.54 power lock in my Jag along with a Yank SS3600 stall and it seems perfect to me. It'll run 70-80 on the highway if you want and have pulled a 1.74 60' at the track. I don't think about mileage because it's hard not to flash the convertor for the fun factor. It's also been in car for 20 years.
I was also wondering will changing out gears, affect the way the car will shift down.
Thread Starter
Launching!
Joined: Apr 2019
Posts: 206
Likes: 11
From: Bay area
Thread Starter
Launching!
Joined: Apr 2019
Posts: 206
Likes: 11
From: Bay area
And if I don't like it, I'll just go up to a 3.73
Also what you guys think about an 3600 stall with this set up?
