1978 cj 7

[Blake Rogers]

Hello everyone,

I have just purchased a 78 CJ7 that has a AMC 304 V8 auto Transmission , and a QuadraTrac Transfer Case . I want to put in a four speed Transmission , with a 350 motor. However i do not want the QuadraTrac Transfer Case . I would like to know what Transmission to put behind of the 350 and then what Transfer Case do i need to get. Having said that would i have to make axle changes due to line up issues? I just have no jeep knowledge so please point me in the right direction.

 

[elwood blues]

Hi Blake, welcome to the site from just down the road in Williamsburg :ww:


I don't know the answers to many of your questions, but I have read that you'll need to change your rear axle because of its offset diff. The SBC 350 swap is pretty common, if you do a search I know there have been several good write-ups detailing the swap.

 

[mtnwhlr]

I think the best way to do this is find a doner 4wd truck and swap the motor, Transmission and Transfer Case to your Jeep and as Elwood said you will have to find a new rearend. IMO

 

[Saddle Tramp]

Welcome to the Jeep obsession! Another option is to stick with the AMC V8 just upgrade to an AMC 360. They are cheap and plentiful in the bone yard and will save you a lot of money/trouble as it will be a 100% direct bolt in for your AMC 304 , and can be juiced up just as much as a 350 if hp is what you are looking for.

For the Transmission stay with the T-18 , either CJ or Ford, with the wide ratio 6.32 low as again this will require minimal hacking and whacking to complete the install. Jeep offered the T-18 as a factory option for the 1978 CJ so the swap can be done with mostly used parts.

The other issue is the Transfer Case to differential alignment as the rear end is offset due to the Quadra Tract case. Two options, one is to change out the rear end with a centered diff, and the other is to leave the rear end alone and use a large hole Spicer 18 Transfer Case (which is offset like the Quadra Trac case and will bolt to the CJ T-18 ). If you replace the rear end with a centered diff then you can use a Dana-Spicer 20 Transfer Case as it will also bolt up to the T-18 Transmission . (Don’t be confused, T-18 = Transmission , Spicer 18 = Transfer Case ) This was a factory combo and the transfer cases are relatively cheap and available. You may need to change the axle gearing so the front matches the rear but a Dana 44 axle can be had that once again will be a direct bolt in; look for a 1972 to 1975 CJ axle or one from a 1972–1973 Commando.

As most on this board know I’m a proponent of keeping your Jeep, Jeep, not Chevy but more import, I’m against hacking up what is left of the vintage Jeep iron that is available and see no reason to spend money on adaptors when used OEM parts will get the job done.

Try these:

http://www.jeeptech.com/convtrans/cjt18/

http://www.jeeptech.com/convtrans/fordt18/index.html

 

[Fastatv]

Saddle Tramp had mentioned the AMC 360. That's what I have in my 76 CJ, the engine is stock, but very impressive. Do you have the GM Turbo 400 Transmission ? Mine has that also....and the GM Turbo 400 is a tough, very reliable. Anyway, let us know what you do. Jeeps are simply a blast!