So how much of a difference will a new rear end/new gears make

[oldmansmonte]

So soon I should be ordering a new rear end for the Monte. I've researched Spohn and Strange and a few others. Seems like there will be nice options available. I plan to do a 12 bolt with 3:73 gears and posi. I currently have the stock 7.5 rear end with 2:73's with the 1 wheel peel and the car rips pretty good as is, but could be better. How much of a difference in driving experience can I expect? On the thruway I never go more the generally 20 Miles at most and mileage isn't a huge concern.

 

[SoFloG]

It will feel like the difference between a slow fart, and a gokart.

 

[Yav8]

Not sure what motor you have or plan on using. The 7.5 will handle a good amount of power unless your on slicks and beat it hard. Unless you really want to spend the money for the 12 bolt you could just upgrade the posi and add a set of new gears. To really save money one could just get a posi from a early 26 spline S-10 blazer or pick up and it would or should come with at least a 3.42 or a 3.75 gear set already. You would need the pinion gear along with the ringgear and posi. Early S-10 had the 26 spline and I think later 88 and up had the 28 splines. Just food for thought.

 

[oldmansmonte]

Not sure what motor you have or plan on using. The 7.5 will handle a good amount of power unless your on slicks and beat it hard. Unless you really want to spend the money for the 12 bolt you could just upgrade the posi and add a set of new gears. To really save money one could just get a posi from a early 26 spline S-10 blazer or pick up and it would or should come with at least a 3.42 or a 3.75 gear set already. You would need the pinion gear along with the ringgear and posi. Early S-10 had the 26 spline and I think later 88 and up had the 28 splines. Just food for thought.

I have the GM performance 350 rated 330hp. I run a TBI setup so I'm only at about 240hp and 300 ft lbs right now. After I do the rear end I plan to do the GM ramjet Multi port fuel setup. The reason I want to do the rear end next is dollar for dollar I think it will be the best bang for the buck and the easier upgrade to execute. What's the point of having a great motor setup with wimpy gears holding it back? Every RWD car I've had has had granny gears.

88' Monte 4.3, 2:73's
96 Roadmaster Wagon 2:93's
(Current 85) Monte 2:73's
(Current 95) Caprice Wagon LT1 with 2:55's(puke).

I've yet to town a V8 RWD with decent gears. Plus I hear these 7.5's tend to blow up. Plus wouldn't the 26 spline be a really weak link?

 

[Longroof79]

The gears will definitely wake up the performance of the car, especially from a take off. If you have overdrive, you'll be fine out on the highway. Would it be cost effective going with the 12 bolt rather than upgrade your 7.5? It also depends on how you plan to drive the car. Do you plan to race it, drive hard, etc.? If it will be driven hard, the 12 bolt might be the way to go.
Granted, the 7.5 won't be as strong as a 12 bolt, 8.5, 8.8. 9", etc.

 

[oldmansmonte]

The gears will definitely wake up the performance of the car, especially from a take off. If you have overdrive, you'll be fine out on the highway. Would it be cost effective going with the 12 bolt rather than upgrade your 7.5? It also depends on how you plan to drive the car. Do you plan to race it, drive hard, etc.? If it will be driven hard, the 12 bolt might be the way to go.
Granted, the 7.5 won't be as strong as a 12 bolt, 8.5, 8.8. 9", etc.

I do tend to drive hard and occasioanly take it to the track so the bigger rear end will definitely be needed. I have OD also as a have a 2004r.

 

[Kwik_Cutty88]

I swapped from a 2.56 to a 3.73 (still non posi ) over the summer and wow what a difference. The car actually gets out of the hole now, and feels way faster. My crusing rpms only jumped a couple hundred rpm up.

 

[Longroof79]

I do tend to drive hard and occasioanly take it to the track so the bigger rear end will definitely be needed. I have OD also as a have a 2004r.

Well, I guess a beefy rearend and a set of gears will certainly be beneficial then. You may eventually think about having the 200-4R gone over and built with a few upgraded parts. .

 

[oldmansmonte]

I swapped from a 2.56 to a 3.73 (still non posi ) over the summer and wow what a difference. The car actually gets out of the hole now, and feels way faster. My crusing rpms only jumped a couple hundred rpm up.

Cool that's what I'm hoping for.

 

[oldmansmonte]

Well, I guess a beefy rearend and a set of gears will certainly be beneficial then. You may eventually think about having the 200-4R gone over and built with a few upgraded parts. .

Already been done by Competiton Transmission in North Tonawanda NY. World class shop and the owner did it himself to make sure it was right because the 2004r as we know requires some know how. Thanks for the tips though. Really looking toward to getting this done.