How to improve the rear-end

[t_visker]

I want posi traction and 3.73 gearing.. where can I order this or get this from???? Someone please point me to the right direction I want to get this done when I or shortly after I put in the 350 cid motor..

[orange442]

What year is it and what rearend does it have? Can't help you if you don't give needed info

[t_visker]

it's an 87 cutlass supreme brougham.. im not sure what rear end i have .. how do i know??

[orange442]

You have a 7.5" rearend in that car. Your best bet is to find a complete rear rearend out of an 85-88 Monte SS, They all had 3.73 gear and many had the G80 posi. They will bolt right in and there are many of them out there. They did come in other G-body cars like T-Type/Grand National and Hurst Olds up to 83. In 84 these got 8.5" rears which are 2 to 3 times higher in price than the SS rears. Go for the Monte SS rear and it will be all you ever need, Hope this helps.

[t_visker]

ok i dont want to take the trouble of swapping the rear end..

do i have 10 bolt 7.5".. i finally got the 350 in their.. so now its time to improve the back

where can i get posi units at??

and also since i have the OD should i do gearing bigger than 3.73.. like 4.10???

also where can i find these gearings at??

im just lookin for the best 1/4..

[orange442]

It is actually easier and cheaper to change a whole rearend out than to change out the carrier and gears. There are a lot of measurements that have to be done and tight tolerances that have to be set by someone that has done it before. It can cost a lot over and above the cost of the gears and posi unit and probably a rebuild kit. If cost is no object, you can order everything through various parts sources such as Summit or Jegs. Then, find a person that can install everything in your car. Be prepared to pay big bucks doing it this way.

[t_visker]

thanks for the help orange442.. its really appreciated..

anyways.. so what are all my options for a rear end without going out and buying a new one for over a grand..

you said 85-88 monte carlo ss but i cant find any of those in our junkyards.. is their anything else??

witharound 300-325 hp can i get away without messing with the rear end?

[orange442]

You will probably have to get online to find parts that you can't find in your area. Some other cars had these rears like Buick t-types, early hurst olds, and some pontiacs. About 84 up the Hurst and 442 cars along with the Buick T-Type and GN came out with an 8.5" rear but they are hard to find and usually very expensive when found. Try online sources such as gbody.org , maliburacing.com and others. Just do some searching and you will find what you want. An MCSS rear is capable of handling 300-325 horse no problem.

[t_visker]

Is posi really that big of a deal if I'm pushing less than 350 horse??

I have a chance to get some 15x7, 15x8, or 15x10 wheels for the rear..

Should I go with the wide tires or the rear end.. I understand gearing and posi is a big deal.. but I'm not pushing 500+horses.. I am new to the car world and am just trying to understand all this.. please bear with me..

also I cant find a monte carlo ss rear anywhere!! I am in brookings, sd and theirs not much around here.. those cars are very rare.. I have all tools imaginable to use on any project for school..so if I could get a posi unit and 3.73 gearing and do the work myself is it worth it then? thanks for the help its super appreciated..

Also what size rims should I go with.. out of those choices..

[orange442]

Wheels and tires: 7" front 8" rear is the best combo, no 10"-too wide for the car.

Posi units: They are only important if you want both tires to grip when you accelerate. Spinning one tire is also not cool!

Gears: Less important because all they do is compound the torque and make it easier to spin tire(s). Also will hurt gas mileage considerably!

Parts:Look on the sites I gave and search for other like sites, this stuff is always coming up for sale in all areas of the country. Also check ebay, they always have this stuff for sale.

SD: I have talked to 2 gentlemen just lately up in your area about parts for some of my other cars so there are parts around. Just be patient and persistent and you will find what you are looking for.

[t_visker]

"Wheels and tires: 7" front 8" rear is the best combo, no 10"-too wide for the car."

So what If I do 14x6 front and 15x8 rear?

So is rear end even that big of a deal then? I will be producing under 350 hp.

I would love to get way without doing rear end work but if it is a big factor to the speed of my car I will do it.

Money is a huge factor so of course if rear end won't do that much for me I would love to put my money towards other stuff for the car.

Also gas mileage is not a problem because the car will get driven to car shows and nice days only. And I live in SD so we know that isn't to often

Thank you again Orange 442 for the help!!