1973 Challenger Rear End

[Fordication]

What case and rearend would a 1973 Challenger with a 318 come with. 489?

 

[Chryco Psycho]

Yes

 

[pschlosser]

maybe a 7.25 (the smaller) rear end.

 

[Vaanth]

What case and rearend would a 1973 Challenger with a 318 come with. 489?

The 1973 Challenger was only available with the 8-3/4" rear axle. The only 8-3/4" axle center section in 1973 was the 2881489 housing, aka "489", with a 1-7/8" pinion.

The standard gear ratio for the 1973 Challenger was as follows:

• 318 or 340 with 3-speed manual transmission: 3.23:1
• 340 with 4-speed manual transmission: 3.23:1
• 318 with automatic transmission: 2.76:1
• 340 with automatic transmission: 3.23:1

The optional gear ratio and/or Sure Grip for the 1973 Challenger was as follows:

• 318 with 3-speed manual transmission: 3.23:1 Sure Grip
• 340 with 3-speed manual transmission: 3.23:1 or 3.55:1 Sure Grip
• 340 with 4-speed manual transmission: 3.23:1 Sure Grip or 3.55:1 Sure Grip (with A36 package)
• 318 with automatic transmission: 3.23:1
• 340 with automatic transmission: 3.23:1 Sure Grip or 3.55:1 Sure Grip (with A36 package)

The A36 Performance Axle Package included the 3.55:1 ratio gear set with Sure Grip, plus a 26" Mx Cooling radiator with shroud and power steering oil cooler (if equipped with power steering).

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[moparleo]

Remember that when it comes to original parts on Mopars, the books are not always 100% accurate.
My last 73 Challenger was one owner, original running car .
My 318, 73 Challenger came with a 741 pig.
If you can find a good 742, it is plenty strong an easier to set up than a .489. Much less expensive too.

 

[Fordication]

The 1973 Challenger was only available with the 8-3/4" rear axle. The only 8-3/4" axle center section in 1973 was the 2881489 housing, aka "489", with a 1-7/8" pinion.

The standard gear ratio for the 1973 Challenger was as follows:

• 318 or 340 with 3-speed manual transmission: 3.23:1
• 340 with 4-speed manual transmission: 3.23:1
• 318 with automatic transmission: 2.76:1
• 340 with automatic transmission: 3.23:1

The optional gear ratio and/or Sure Grip for the 1973 Challenger was as follows:

• 318 with 3-speed manual transmission: 3.23:1 Sure Grip
• 340 with 3-speed manual transmission: 3.23:1 or 3.55:1 Sure Grip
• 340 with 4-speed manual transmission: 3.23:1 Sure Grip or 3.55:1 Sure Grip (with A36 package)
• 318 with automatic transmission: 3.23:1
• 340 with automatic transmission: 3.23:1 Sure Grip or 3.55:1 Sure Grip (with A36 package)

The A36 Performance Axle Package included the 3.55:1 ratio gear set with Sure Grip, plus a 26" Mx Cooling radiator with shroud and power steering oil cooler (if equipped with power steering).

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Thank you. I am looking at a 3.55 sure grip rearend on the internet and wanted to make sure it would work before I make an offer. He is asking 800 a rebuilt one and I think I paid close to that for my mustang with positrack.

 

[mrmopar340]

Find out if it's cone or clutch in the sure grip. Clutch is stronger and see if you can buy the whale oil friction modifier to keep it working properly. It may have been rebuilt with a non Mopar sure grip .as well like an Eaton unit. Just be sure to ask so you know what to use in it.

 

[pschlosser]

He is asking 800 a rebuilt one and I think I paid close to that for my mustang with positrack.

that isn't a bad # for a properly rebuilt one. freight may hurt if that's a factor. that isn't far from having one rebuilt by a shop, if you want some guarantee against a poorly built one with lots of whine and noise.