What Ratio Should I Change the Chevelle to?

[Dwn4BassAlan]

I'm leaning pretty heavily towards 3.55, but is there one in between 3.73 and 3.55 that could work? I thought they made 3.64's but I remember it being for a Buick..so I don't know if it would work in or if they make ones for a GM Chevy?

[Brandonbkd]

I'd just do 3.55 because you're not drag racing and cruising down the highway in 4th would suck with a higher ratio

[CaPRiCEx383]

I would personally go for 3.42's for a driver. It's what I have in my caprice now, and even though I haven't drove it yet, I know it will be a bit more forgiving as a daily driver over anything higher.

[Dwn4BassAlan]

Anyone know off the top their heads what the standard tire size is for 71 chevelles? I was thinking between 25"-27" area?

[Dwn4BassAlan]

I would personally go for 3.42's for a driver. It's what I have in my caprice now, and even though I haven't drove it yet, I know it will be a bit more forgiving as a daily driver over anything higher.

lol what do you mean forgiving? In the sense of easier to control, or gas mileage? Or both?

[Evan_P]

Well from what I found in 5 minutes of searching online, stock size is 215/70R14. That converts to 25.9 inches tall. I also found you 4th gear ratio to be 1:1. Correct me if I'm wrong there. So with those numbers here is what I can give you.

2.73 rear with 1:1 4th, 26" tires @ 55 mph = ~1940 rpm, 2.73 rear with 1:1 4th, 26" tires @ 45 mph = ~1588 rpm

3.55 rear with 1:1 4th, 26" tires @ 55 mph = ~2523 rpm, 3.55 rear with 1:1 4th, 26" tires @ 45 mph = ~2064 rpm

3.73 rear with 1:1 4th, 26" tires @ 55 mph = ~2651 rpm, 3.73 rear with 1:1 4th, 26" tires @ 45 mph = ~2169 rpm

4.10 rear with 1:1 4th, 26" tires @ 55 mph = ~2914 rpm, 4.10 rear with 1:1 4th, 26" tires @ 45 mph = ~2384 rpm

Again, if you have any corrections let me know and I will adjust accordingly.

[ROLEXrifleman]

1:1

[truthsayer]

what ever you decide, don't go back to who installed your clutch. your clutch should last much, much longer than a year.

[Dwn4BassAlan]

what ever you decide, don't go back to who installed your clutch. your clutch should last much, much longer than a year.

No, it wasn't installer error, it was a combo of things. It's my daily driver, (about 30 miles a day average) all through the hills, city, neighborhoods. Nothing but stop and go on a 2.73 gear ratio with a heavy system in the back............ I used that clutch as much as it would be if it was in there for 5 years.

[Broke_Audio_Addict]

what ever you decide, don't go back to who installed your clutch. your clutch should last much, much longer than a year.

No, it wasn't installer error, it was a combo of things. It's my daily driver, (about 30 miles a day average) all through the hills, city, neighborhoods. Nothing but stop and go on a 2.73 gear ratio with a heavy system in the back............ I used that clutch as much as it would be if it was in there for 5 years.

If anything the steeper ratio is going to make your clutch wear faster. I'm guessing your premature failure has to do with your driving habits more than anything else. How many miles did you put on the clutch?

Do you ride the clutch a lot while driving? Stand on it while at a light? Use it to slow you down? Also do you downshift while slowing and use the trans to help you stop? Use it told hold you in place at a hill stop? These are all things that can wear a clutch out fast. If you haven't upgraded the clutch now would be a wise time to do so since you plan on changing the gear.

I also think you should do these things yourself. you are smart enough to design and build a bad ass sub you should be able handle these 2 jobs yourself. you would be surprised how easy a rearend and clutch job is. should take you no more than a day or 2 if your inexperienced.