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SJ Cherokee


Mar 29, 2021
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Hi all, cross posting this from the other site, no replies. So gonna see if I get some here.

I have a '74 Cherokee that I want to do an engine/transmission swap on. I want to install a slightly warmed over SBC 383 and a 700R4. The T/C is a QuadraTrac with low range. I'm running 35's on my stock 44's. I'm also planning on adding one piece axles and a disc brake conversion on the rear. I figure while I'm in there I might as well add a locker. Since I'm adding the locker, I'm wondering what would be a good gear ratio to run. I think I have 3.54's installed, not sure and I'm not in a position to verify ATM. Most driving will be on road. I want to tow occasionally (<5,000 lbs) with it and do some wheeling. Nothing extreme, live in Northern Idaho, so some logging trails and back roads in and around the bordering states and might want to hit Moab sometime in the future.

What backchat said. With overdrive in the 700r4, 4.56-4.88 on 35s will likely be your best bet. 4.11 if you want some more highway economy and don't need to crawl as much.
Thank you for the replies. I've been plugging in numbers into various calculators and was initially thinking 4.10's but upon reflection and many YouTube videos I'm beginning to think that 4.27's might be a good compromise. The main problem I was having was that most calculators ask you to input an engine RPM at, say, highway speed in order to get a solution from the calculator. As I haven't driven a V8 Chevy in decades, I could only guess about 2,800. So I'm hoping that gear choice will work for an all purpose vehicle.
The calculator posted above was pretty good and informative since it auto filled cells for transmission and transfer case.
I would ditch the q-trac t-case, Run a Dana 18 if you don't want to swap the rear axle, otherwise use a GM t-case with a passenger front drop. The chains wear rapidly in the q-trac. With a 250 hp 401, you might get 25,000 miles on a USA made chain before they start to skip under load, especially if you tow or run heavy. The low range ratio sucks, too.

If the engine is pretty mild, I would shoot for in the low 2000s for a cruise RPM if you don't tow with it. 2800 if you want to tow with it (Wherever peak torque is on the engine setup)
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