Hello all I am new to the jeep work bought my self a 72 cj5 it has the 304 and is a 3 speed it has 33 inch tires locked rear axle and has almost no rust and a good paint job I was just wondering what crusing speed it will do with out being to high in the rpms
Ok so you need to find out what you have in it. Crawl under and around looking for numbers on each piece of drive train, mine (84 cj7 stock ish) has a t176-dana 300-amc20 axle...looking up each one I found what gears I have, then use a website like.... http://www.grimmjeeper.com/gears.html
And plug in your numbers.
Hope this helps, I did it for fun, and I doubt ill ever do 85 MPH in it...but math says with 31's I can. Yeah not happening, but 3mph at idle...yeah I can crawl like that
Hmm with 33's...I would disconnect the u joints and turn a wheel. Count turns and get your diff ratio, wouldn't hurt to do front and rear, just to make sure one didn't get changed and the other stock, its 8 little bolts and easy to get to the u joints to remove them.
A '72 would have come with 3.73 axle ratio standard, or 4.27 optional. Both are fine for highway travel. If the Jeep is in good condition, you can drive as fast as traffic and your nerve and ears allow. The motor will be fine at those speeds.
With 33s at 85 mph, you'll be turning 3200 with 3.73s and 3700 with 4.27s. A 304 in good condition will run indefinitely at those speeds.
If you do not feel comfortable at those speeds, either you have worn parts or the suspension has been improperly modified. Jeeps from this year were fine at above legal speeds direct from the factory, even with comparatively short tires.
I prolly have worn bushings ext.. they are on my never ending list of parts to replace.
Getting an original back seat is more about luck, a lot of people seem to remove them and sell on eBay/Craigslist, or get a bench seat from a mini van that will fit, not sure the year, measure and go to pick and pull, then get seat covers to make em all match.