3.73 rear end vs. 3.42 rear end? - Chevy Nova Forum
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Old 30th-August-2006, 09:56 PM   #1
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3.73 rear end vs. 3.42 rear end?

Greetings,

I've got a 3.42 ring and pinion in my Nova now and debating on putting in a 3.73 ring and pinion. I want to feel a bit more torque off of the line and I would think this would help, plus I think it'll match my cam (292H Comp Cams) and converter better (TCI Break-A-Way). Other than a drop in gas mileage and the need for another speedometer gear, what other negatives are there to this swap?

Jason
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Old 30th-August-2006, 10:27 PM   #2
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gears

Jason, I have 373's in mine with a super t-10. I'm not sure what the gear ratio in the tranny is but I was thinking of going down some in the rear end. When I drive down the highway in the slow lane it seems like everybody else is going 100 miles an hour by me and I'm tacking 3000 rpm. What type of driving will the car see???


Steve W
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Old 30th-August-2006, 10:54 PM   #3
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Greetings,

I drive it all over the place...highway and around town. I do get on it sometimes, barking the tires when it shifts and such, but not often. I know the 3.42 is a lot more practical (I won't be racing or anything like that) but for some reason I just think the car will perform better with the 3.73. Right now 3000rpm is about 70mph with my setup in third gear.

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Old 30th-August-2006, 11:04 PM   #4
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Man that 292 needs more converter! That would wake it up off the line more than anything. But, I know a higher stall converter can be a pain on the street. I've got a Breakaway we used with a stock 350, and when I switched to the 383 with an XS274 CompCam, it was a dog off the line. A new convertor fixed that though. Even a 3000 would wake it up a good bit. A 3500 would be even better. The good news is you wouldn't be turning any more rpm at highway speeds than you are now if you changed converters instead of gear. The bad news is, you'd probably see your around town mileage suffer.
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Old 30th-August-2006, 11:08 PM   #5
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I doubt you'll see enough difference to warrant the expense--you could probably put a nitrous system on the car for the same money and see a HUGE difference compared to the gear swap.
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Old 30th-August-2006, 11:15 PM   #6
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On a street driven third gen with a 1:1 high gear and 26" tall tire, the 3.42 gear is pretty close to the ideal gear for all around performance. If you want it to come off the line quicker (and still keep up with interstate traffic), I would second that vote for a looser converter.
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Old 31st-August-2006, 09:13 AM   #7
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+1 for converter over gears.

Kev
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Old 31st-August-2006, 08:53 PM   #8
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I put a 3.73 in my Nova and regretted it--not fun on a 55 mph road--I was at 3000 and still saw everybody passing by. Thats why I am putting a 200r4 tranny and my 3.08 in when i put a big block in. Just my 2 cents worth--: ) --Eric
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Old 31st-August-2006, 09:21 PM   #9
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Why are you putting in a 3.08 and a 200R4? Your final drive ratio in OD will be around 2.09. I'd leave the 3.73's and put in the OD tranny.

Jason: I don't think you will notice enough difference either.
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Old 31st-August-2006, 09:44 PM   #10
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3.42 to 3.73 gears should bump up your RPM's about 300 or so. To get a noticable difference you usually have to go 2 steps but that would be overkill on your application I would think. If you want to see what it would be like just borrow some wheels that are an inch shorter for the rear and sport it around it ='s out to the same difference. 1" of tire is about 1 ratio change.

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Old 31st-August-2006, 09:59 PM   #11
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Greetings,

I ordered a Super Street Fighter TCI converter tonight...Should get it Tuesday. It looks like that'll be the best route and give me about 3400 stall. Hopefully I'll put it in next weekend!

Jason
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Old 1st-September-2006, 04:25 PM   #12
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72 resto,
change the trans b/4 you change the gears. A 2004R with 3.08s may not have a high enough cruise rpm to allow you to get into OD at less than 60 MPH. I have 3.73s with the 2004R and it works pretty well becasuse my cam makes power from 1,500 RPM to 6,200 RPM. Even still, It slugs in OD at less than 1,500. 2,000RPM is right around 65MPH in OD. Even with a big block, if you have a lumpy cam, it may not like OD at less then 60 MPH with those 3.08s.
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Old 1st-September-2006, 05:27 PM   #13
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Quote:
Originally Posted by Jason628 View Post
Greetings,

I ordered a Super Street Fighter TCI converter tonight...Should get it Tuesday. It looks like that'll be the best route and give me about 3400 stall. Hopefully I'll put it in next weekend!

Jason
I hope you have some good, fresh sticky tires on that thing - and vinyl seats or something that clean up easy......
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Old 1st-September-2006, 11:23 PM   #14
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The effect doesn't warrant the effort and expense. You really won't notice that big a change.
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Old 2nd-September-2006, 12:56 AM   #15
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3.42:1 is a better ratio for your application. If you really want more bottom end you could also dump the cam and go to a shorter duration. What's your compression ratio? I probably wouldn't run a cam like yours with less than 10:1.

If you bought the 10" TCI Super Streetfighter I hope you have a trans cooler too because it will be short-lived on the street without one.
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