9 inch Rear/Original Rear

[1979Calais]

I am rebuilding my 1979 Cutlass Calais (frame off). This is my first time restoring a car, so I need help. I am putting a 350 engine with about 350 - 400 hp with a 700r4 trans. I would like to know what rear end I should put in it. My brother in law is trying to get me to put a 9 inch rear in it. Can someone tell me what rear I should put in or just change the gears out in the original one? Also I am not racing the car, but I do want posi track.

Thanks!

 

[CHRIS.O]

If your not racing it then just buy a posi unit or pick up a factory posi 7.5. Don't waste your money on an 8.5 or 9" if your just gonna street drive it and fry the tires occasionally.

 

[1979Calais]

Thanks, I am looking into that. I got a few people that told me $1,500 to redo my rear.

 

[GhettoRacingKid]

If your not racing it then just buy a posi unit or pick up a factory posi 7.5. Don't waste your money on an 8.5 or 9" if your just gonna street drive it and fry the tires occasionally.

+1

Main thing to do is always keep in mind what your are going to be doing with the car and unless your funds are endless keep your head on straight. a 7.5 is good for cruising and stuff. an 8.5 is great for a street car with balls, a 9" is needed for the people (such as myself) who are hitting the track and going to be beating the crap out of the car

 

[G-Body_Vet]

an 8.5 is great for a street car with balls,

I'm leaning towards this option since I'm not planning on track time, but want something than can take a little thrashing on occasion. I thought about just keeping the 7.5" but I don't think it would hold up to 455 torque for long. No point in doing the work twice if I can help it.

 

[GhettoRacingKid]

I think an 8.5 would be perfect for you. and the 3.42 gearing is good for the steets. so no need to really put money into it.

I ran an 8.5 for a year with stock gears and put an aluminum cover on it some new bushings and extended studs and it was great. my needs changed but I knew that was going to be the case.

 

[1979Calais]

Do anybody know what rear came in a 1979 Calais? I am thinking I may hit the track a few times, so I really don't know what to do.

 

[RITTER]

"Track time" would be considered like an every week test'n'tune :idea: If you're going to the track a couple of times, because you just wanna see what it'll run, you do not need a FORD 9" rear. The biggest thing to look into is the cost of properly building your 7.5" rear to the cost of purchasing a complete bolt in 12 bolt or 9" rear :| Parts alone for rebuilding the 7.5" / 8.5" will run you +/- $1,000 ... for like $2,500 you can get a bolt in 12 bolt or FORD 9" :idea: So if someone will PROPERLY build your rear end for $1,500 ... then you can save $1,000

 

[GhettoRacingKid]

Do anybody know what rear came in a 1979 Calais? I am thinking I may hit the track a few times, so I really don't know what to do.

Well what kind of drive train and power are you going to be running? a stock 7.5 can handle a decent amount of abuse. and if your going to the track once in a while your ok, you running slicks, drag radials or street tires.

 

[1979Calais]

"Track time" would be considered like an every week test'n'tune :idea: If you're going to the track a couple of times, because you just wanna see what it'll run, you do not need a FORD 9" rear. The biggest thing to look into is the cost of properly building your 7.5" rear to the cost of purchasing a complete bolt in 12 bolt or 9" rear :| Parts alone for rebuilding the 7.5" / 8.5" will run you +/- $1,000 ... for like $2,500 you can get a bolt in 12 bolt or FORD 9" :idea: So if someone will PROPERLY build your rear end for $1,500 ... then you can save $1,000

Thanks. Most of all, I just want it done right the first time. Paying more money will just push my project out a few more months. I am trying to find the person that told me $1,500 for the build.