3.42's vs. 3.73's

[wicked weather]

I have read discussions about this, but no real numbers. What benefit would you gain on a bone stock Sy running a 13.6 with 3.42's, switching to 3.73's (1/4 mile that is)?? Anyone have actual time differences? I know the obvious loss of Non-existant-to-begin-with topend speed. I am just curious at the gains.....They must be noticeable.

Anyone actually done this?

:scatter:
Devon

 

[Sy769]

No idea


You will have to upshift to fourth before the traps on a stock Sy

 

[Lynn D. Brown]

Rear End Ratio

Rear End Ratio

Devon,

I would think the only gain would be in the 60' time, and every
0.1 there should correlate to ~ 0.15-0.20 sec in the 1/4. And U
would probably lose some of this at top end, which the stocker
has very little of.

The real gains would come if U increased the engine top end and
added a Hi Stall TC. But perhaps U already knew all this general
stuff.

 

[wicked weather]

3.42's vs. 3.73's

I am mainly wondering, because I have a vibration I cannot pin. So I am going to replace the Xfer case <needs it I am sure>, and Driveshaft. If this does not remedy the problem, I will look at the rear. If it IS the rear, I might as well look at the front diff too. Thus my questioning upgrading the ratio's. My Sy is Not Stock at all, NOT running right, right now, <seems like years now> but far from stock.

My current setup is an Non governed built 700r, with a 9.5 inch multidisc <can you say nasty?> 2800 stall convertor. Stock Heads, and front and rear diffs, KB Cam, Fuel mods., ECM etc. Killed 12.70 stangs with ease

I could hang 130-140 mph next to my friends beasted Trans Am (he says) <before he said Bye Bye>, so I am wondering what I would lose.

Devon

 

[FLSY2730]

Leave the 3.42s in.

 

[jwaller]

multi disc....holy crap I bet that thing pisses off the knock sensor...I had a look at one and that thing rattled it pulled out 18 deg timing at idle... if you do any gear changin I'd go 3.23....

what all have you done to trace down vibration?....have you removed shafts? replaced them had them rebalanced.....replacing the xcase is the last place I'd look...I've only heard of a very few of them goin out...and that was on very high HP trucks..

 

[SY756]

I agree with John, check all of the drive shafts first, I have been around these trucks for 6+ years and can count on one hand how many transfer cases I have heard of going out. And if you are going to change gears go with the 3.23's. Since you have a higher stall it shouldn't hurt you any and probably will help you out in the 1/4. If you went with the 3.73's you would, well depending on your engine build, be shifting into overdrive and with the 3.23's you could keep it in drive and keep it in the power band.

 

[smeagol]

Buick guys typically stick with 3.42's until they go real fast, with motors that spin to higher RPM. This is also in a car with a poor 1st gear compared to the 700r4. The 700 makes a 200 or 350 tranny'd car feel like it has 3.73 or 3.90 in first gear. Bottom end isn't lacking in our trucks, just hold more boost at the line. Gearing it for 2nd and 3rd gear, for the best midrange/top end through the traps is more the issue IMO.

Just my $0.02

 

[turbodog]

[quote="... if you do any gear changin I'd go 3.23.....[/quote]

Is there a 3.23 gear set available for the front diff? Anyone know the RPO code for a 4X4 with 3.23 gears? I'd definitely go there in my daily driver S-Blazer.....TIA!

 

[jwaller]

GU5 is the RPO code....and yes 3.23 woudl be the better option as I said before... G80 is locking rear diff.....