Workin on my build, options for rear end...
January 3rd, 2013, 07:46 PM
#1
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Join Date: Mar 2011
Location: SE Michigan
Posts: 56
Workin on my build, options for rear end...
When working on cars I'm a novice at best, so any feedback would be appreciated. I have a Cutlass CV w/a stock 350. I'm swapping trans to a 200-4R & 3.42/3.73 gears,
Question: What is the likely hood of being able to find 3.42/3.73 gears for my "current rear end" or should I just get one built?
Side note...I also want to install disc brakes in rear too(I have front disc & I just want disc all the way around).
For those interested, I included my original post with some build ideals/plans.
https://classicoldsmobile.com/forums...ster-tips.html
Thanx
Question: What is the likely hood of being able to find 3.42/3.73 gears for my "current rear end" or should I just get one built?
Side note...I also want to install disc brakes in rear too(I have front disc & I just want disc all the way around).
For those interested, I included my original post with some build ideals/plans.
https://classicoldsmobile.com/forums...ster-tips.html
Thanx
January 3rd, 2013, 10:15 PM
#2
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Join Date: Aug 2009
Location: Muskegon, Mi.
Posts: 8,616
If your car is the '70 in your avatar, new 3:42's are not available, a couple of members here may have a used set. A good place to check is the parts section @ 442.com. Devos gears and rears (advertises in Hemmings) may have a set. 3:73's were not available for 1970 type O rear end.
January 3rd, 2013, 11:45 PM
#3
Seasoned beater pilot.
Join Date: Jan 2007
Location: Chicago
Posts: 5,468
I have a semi-freshly rebuilt 2004r trans here that you may want to consider if you're not excited about parting with 1500 bucks.
My friend had it built last year by a fellow racer, and he put it in his 72 Buick last fall. He cruised the car around and decided the 350 motor was too slow (it was a 1976 motor), and he is going big block powered now.
Out it came, and I traded him a fresh TH400 and a type o rear end for it. The car is pretty cool. It's a sun coupe.
My friend had it built last year by a fellow racer, and he put it in his 72 Buick last fall. He cruised the car around and decided the 350 motor was too slow (it was a 1976 motor), and he is going big block powered now.
Out it came, and I traded him a fresh TH400 and a type o rear end for it. The car is pretty cool. It's a sun coupe.
January 4th, 2013, 04:08 AM
#4
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Join Date: Mar 2011
Location: SE Michigan
Posts: 56
If your car is the '70 in your avatar, new 3:42's are not available, a couple of members here may have a used set. A good place to check is the parts section @ 442.com. Devos gears and rears (advertises in Hemmings) may have a set. 3:73's were not available for 1970 type O rear end.
. I found the ad below on one of the Olds websites, $1200 seems a bit high...what can I expect to pay (approx) Im in SE Michigan?Ad as listed-------1970W30 TO posi rearend 3:91 super clean- $1200
January 4th, 2013, 04:31 AM
#5
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Join Date: Oct 2009
Location: Erie,PA
Posts: 3,814
My rebuilt 12-bolt O-axle rears are $1400.00. A rebuilt 12-bolt Chevy will be $1500-$1600.00,only because the price of the cores dictate the final price of the total build.
The rears that I have built for guys running the overdrives have had 3:73's,3:90's,or 4:10's. I did a 12-bolt O-axle with 3:90's for another 70 Cutlass,with a 350 & 2004R,and the combo works quite well.We drove 6hrs to my place,and swapped in the new rear,and he drove it 6hrs back.It was great on the highway.
I currently only have 3:90's and 4:10's for the O-axle.
If you went with a 71-72 8.5" 10-bolt your options are 3:42,3:73,3:90,4:10,as well as others.
If you went with a 12-bolt Chevy,your options are 3:42,3:55,3:73,3:90,4:10,etc.
The 71-72 8.5" 10-bolt is the cheapest to buy/build,initially,at $1100.00 for a rebuilt rear.However,when installing this into a car that originally came with the O-axle,you will need your drivshaft shortened,so you need to look at that expense,and add that to the cost,to see what the final cost of the swap is.
I have also found that when guys have swapped from the TH350 to the 200R4,they need to shorten the driveshaft,so if you have to do it anyway,then now would be the time to figure out which rear you want in there.Even when I did the 3:90 O-axle rear for the 70 cutlass,with the 200R4,I found that the stock shaft still needed to be shortened,due to the slightly longer length of the 2004R.It did not have as much clearance as it should.It was good enough to get to my place and back,but it was a little on the tight side,and close to being in a bind,which is not a good thing.
As for the rear discs,you can install rear discs on any of the 3 rears mentioned above.Some kits will fit all,,but some kits might require some clearancing of the caliper brackets,for proper fitment to the axle tubes.
The rears that I have built for guys running the overdrives have had 3:73's,3:90's,or 4:10's. I did a 12-bolt O-axle with 3:90's for another 70 Cutlass,with a 350 & 2004R,and the combo works quite well.We drove 6hrs to my place,and swapped in the new rear,and he drove it 6hrs back.It was great on the highway.
I currently only have 3:90's and 4:10's for the O-axle.
If you went with a 71-72 8.5" 10-bolt your options are 3:42,3:73,3:90,4:10,as well as others.
If you went with a 12-bolt Chevy,your options are 3:42,3:55,3:73,3:90,4:10,etc.
The 71-72 8.5" 10-bolt is the cheapest to buy/build,initially,at $1100.00 for a rebuilt rear.However,when installing this into a car that originally came with the O-axle,you will need your drivshaft shortened,so you need to look at that expense,and add that to the cost,to see what the final cost of the swap is.
I have also found that when guys have swapped from the TH350 to the 200R4,they need to shorten the driveshaft,so if you have to do it anyway,then now would be the time to figure out which rear you want in there.Even when I did the 3:90 O-axle rear for the 70 cutlass,with the 200R4,I found that the stock shaft still needed to be shortened,due to the slightly longer length of the 2004R.It did not have as much clearance as it should.It was good enough to get to my place and back,but it was a little on the tight side,and close to being in a bind,which is not a good thing.
As for the rear discs,you can install rear discs on any of the 3 rears mentioned above.Some kits will fit all,,but some kits might require some clearancing of the caliper brackets,for proper fitment to the axle tubes.
January 4th, 2013, 08:36 AM
#6
Registered User
Thread Starter
Join Date: Mar 2011
Location: SE Michigan
Posts: 56
I have a semi-freshly rebuilt 2004r trans here that you may want to consider if you're not excited about parting with 1500 bucks.
My friend had it built last year by a fellow racer, and he put it in his 72 Buick last fall. He cruised the car around and decided the 350 motor was too slow (it was a 1976 motor), and he is going big block powered now.
Out it came, and I traded him a fresh TH400 and a type o rear end for it. The car is pretty cool. It's a sun coupe.
My friend had it built last year by a fellow racer, and he put it in his 72 Buick last fall. He cruised the car around and decided the 350 motor was too slow (it was a 1976 motor), and he is going big block powered now.
Out it came, and I traded him a fresh TH400 and a type o rear end for it. The car is pretty cool. It's a sun coupe.
January 4th, 2013, 12:43 PM
#7
Seasoned beater pilot.
Join Date: Jan 2007
Location: Chicago
Posts: 5,468
All I can remember of what he told me: it has new higher performance boost valves, a shift kit, and had been modified to accept extra clutch packs.
I'm assuming those are just standard upgrades over factory items, and that this trans isn't quite ready to handle a 500 horsepower mill. Just upgraded a bit since it was going from 307cubes to 350 cubes.
Does $500 and a 90 day warranty sound fair? So long as a competent shop adjusts the TV cable, I'll have plenty of confidence in it.
January 5th, 2013, 08:08 AM
#8
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Thread Starter
Join Date: Mar 2011
Location: SE Michigan
Posts: 56
Unfortunately, I do not. I may still have the contact info for the fellow who rebuilt it though, and could try getting a hold of him.
All I can remember of what he told me: it has new higher performance boost valves, a shift kit, and had been modified to accept extra clutch packs.
I'm assuming those are just standard upgrades over factory items, and that this trans isn't quite ready to handle a 500 horsepower mill. Just upgraded a bit since it was going from 307cubes to 350 cubes.
Does $500 and a 90 day warranty sound fair? So long as a competent shop adjusts the TV cable, I'll have plenty of confidence in it.
All I can remember of what he told me: it has new higher performance boost valves, a shift kit, and had been modified to accept extra clutch packs.
I'm assuming those are just standard upgrades over factory items, and that this trans isn't quite ready to handle a 500 horsepower mill. Just upgraded a bit since it was going from 307cubes to 350 cubes.
Does $500 and a 90 day warranty sound fair? So long as a competent shop adjusts the TV cable, I'll have plenty of confidence in it.
J, I'm still checking out all my options but ill surely consider the one you have. Do you have any pictures of the unit?
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