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I'm a newby although I've had my 77 CJ7 w AMC 304 and T-150Transmission for forty ! years. I'm driving 3 hours each way for hunting and deciding it is time to swap an automatic behind the AMC 304 and not wind out the motor on the highway. What options are there for the AMC 304 and mating with a Dana 20Transfer Case ?
Agree with "hole" above. You need a tranny with overdrive for highway speeds while keeping the RPMs lower. Of course your tire size and axle gearing are all also factors in final RPMs. I have a SBC 350 with the 700R4 that has overdrive. Running 4.56 gears and 35" tires, I am doing about 2600 RPM at 70mph. Here's a great RPM calculator: RPM Calc
You stated you want an automatic tranny. The AX15 would give you overdrive and bolt behind the AMC 304, but it's still a manual. Keep the 304's flywheel if you go this route.
I don't know of an AMC direct fit auto trans with overdrive. You'll need to consider other trannies like from GM (700R4, 4L60, etc) to get overdrive. Novak offers adaptors to put GM trannies (like the 700R4) behind...
Welcome!
I dont believe you will gain anything with factory bolt in options, as I understand it they are all 1-1 final drive ratio same as all 3/4 speeds. I would poke around on Novaks website for options and ideas. I would think its probably easiest and cheapest to see if an AX15 (5spd) is doable. Please tell us more about your 7, gears, tire size etc.
Agree with "hole" above. You need a tranny with Overdrive for highway speeds while keeping the RPMs lower. Of course your tire size and axle gearing are all also factors in final RPMs. I have a SBC 350 with the 700R4 that has Overdrive . Running 4.56 gears and 35" tires, I am doing about 2600 RPM at 70mph. Here's a great RPM calculator: RPM Calc
You stated you want an automatic tranny. The AX15 would give you Overdrive and bolt behind the AMC 304 , but it's still a manual. Keep the AMC 304 's flywheel if you go this route.
I don't know of an AMC direct fit auto Transmission with Overdrive . You'll need to consider other trannies like from GM (700R4, 4L60, etc) to get Overdrive . Novak offers adaptors to put GM trannies (like the 700R4) behind an AMC engine (like the AMC 304 ). Use their part # 437AMC-2 for this combo. Then you'll also need their adaptor for the Dana 20Transfer Case on the rear of the GM tranny. Novak also offers this as well, part # 178-4-10 (depending on input gear spline count). With these two adaptors and the GM auto Transmission , you're getting a lengthy overall drive train. In my case (the SBC with 700R4 and Dana 300 ) I used Novak's adaptor for the Dana 300 (thinner than their adaptor for the Dana 20 ) and did not need any adaptor for the engine/Transmission combination. Even with that, I had to move my engine as far forward as I could and also have angled spring perches on my rear axle to keep the rear drive shaft angle from getting too steep and causing excessive vibration. Now I do have a 4" suspension lift, so that does contribute to my steeper drive shaft angle as well.
Not against the AX15 if it will solve a problem at highway speed. THX. Will the AX15 bolt up with the Dana 20 ? So with this calculator and present set up the RPMs at 70 mph would drop from 2686 to 2100.
