yourpc48 Posted May 31, 2012 Report Share Posted May 31, 2012 I am getting an Explorer rear for my car in the next week or so. My father inlaw got 2 Explorers for scrap this week and I will be getting a rear end out of one of them as well as some other parts Im sure. One is a 97 Explorer sport and the other is a 2000 Explorer 4 door. I will be looking for the one with the highest gear ratio not to excede 3.50. If it goes any higher I dont think the old beast could handle it. Ive been telling him 3.50 to 3.73 so well see. I cant be too picky since FREE is a very good price! Both of these years have disk brake rear ends so my car will then have 4 wheel disk and I will definitly be changing the master cylinder as well. I think I have a (Get creative) plan for the master. I will probably be using all Explorer parts for my swaps so that someone could get all the parts off of one rig and not have to go searching for anything. Quote Link to comment Share on other sites More sharing options...
yourpc48 Posted June 1, 2012 Author Report Share Posted June 1, 2012 I do not have a tach on my car but I know that the engine has to turn a pretty high RPM to get up to 55 (actual 55 is 70 on the spedo) with the setup I have right now. My goal is to be able to go about 60-65ish with no overdrive and not be overworking the engine. But still be able to drive around town. I do computer service work and do a lot of driving in town and from our town to other towns close to us. The 3 towns close to us are all within about 20 to 30 miles from us. When I get to these Explorers to pull the rear ends I have 2 choices. 3.73 or 3.27. I believe that the 3.27 is just a little too high a ratio. The 3.73 is a little lower than what I wanted but acceptable for the Lhead. I suppose that with the 3.73 I can put taller tires on and get a little more top speed out of the car. Anyone out there running anything below a 3.50 gear ratio with the old flatty in thier car? Happy with the results? Before I pickup a rear end I would like to hear results of other swaps. I have 4.11 gears now and 225 70 15s on the car now. I think I could get the result I am looking for with 3.73 and 235 70 15s. Hmmmmm Thanks.... 1 Quote Link to comment Share on other sites More sharing options...
Young Ed Posted June 1, 2012 Report Share Posted June 1, 2012 I have a 3.73 in my 48 club coupe with 215 70/75 r15s. At 65 I'm turning just under 3K rpm. Quote Link to comment Share on other sites More sharing options...
Robert Horne Posted June 1, 2012 Report Share Posted June 1, 2012 My 38 has about a 3 1/2 gear in the rearend, 235/75 tires, 3 speed trans. It does real well around 30 to 55, about 2500 on the tach. Above that, the engine goes high up the tach. Not sure how acurate my tach is. I believe my 38 would benefit from a 3 1/4 rear with the 3 speed, but I am trying to get a 5 speed/ 3 1/2 rear combo working. I have a 3.73 rear to try with the 5 speed if the 3 1/2 does not feel ok... Quote Link to comment Share on other sites More sharing options...
greg g Posted June 1, 2012 Report Share Posted June 1, 2012 (edited) go here and stop guessing. Plug in your knowns, and let it tell you what rpm to speed ratio is. Use 1 to 1 for the transfer case. http://www.4lo.com/calc/gearmetric.php http://www.4lo.com/calc/gearratio.php but roughly a 3.73 will yield aproximately a 10% change (reduced rpm) compared to a 4.11. In my case my set up 4.11 with 225 75 15 tires 3200 rpm is 62 mph. with a 3.73 rpms at 62 would drop 10% or 320 to equal 2880. My opinion is that 70 series tires are to short for our cars you need a tire between 27 and 28.5 inches in diameter to approximate the stock tire. Edited June 1, 2012 by greg g Quote Link to comment Share on other sites More sharing options...
yourpc48 Posted June 1, 2012 Author Report Share Posted June 1, 2012 Thank you guys. Greg. Thank you for posting the charts. I think I may have seen something like those in another post (Might even be the same ones). I guess I didnt make myself clear enough so let me clear it up a little here. My wondering was not for final RPM but experience with the gearing from the trans. I think that the 3.27 would be great for highway but from what I have seen in the threads on the forum the 3.27 might be pretty tall for our first gear. Any thoughts on that would be appreciated too. Quote Link to comment Share on other sites More sharing options...
greg g Posted June 1, 2012 Report Share Posted June 1, 2012 I think 3.55 would be the limit with the standard three speed and normal diameter tires. Quote Link to comment Share on other sites More sharing options...
ptwothree Posted June 1, 2012 Report Share Posted June 1, 2012 I can tell you from my own experience, that trying to get going on an uphill incline with a 3.27 gear will be a good test for your clutch. That's with an engine in good cond. Low compression and you ain't goin nowhere. I think a 3.55/3.73 with some type of o.d. gearing is the way to go.... Quote Link to comment Share on other sites More sharing options...
yourpc48 Posted June 1, 2012 Author Report Share Posted June 1, 2012 I can tell you from my own experience, that trying to get going on an uphill incline with a 3.27 gear will be a good test for your clutch. That's with an engine in good cond. Low compression and you ain't goin nowhere.I think a 3.55/3.73 with some type of o.d. gearing is the way to go.... Thank you for the reply. Did you have the stock size (or close to it) tires on that rig? Quote Link to comment Share on other sites More sharing options...
yourpc48 Posted June 1, 2012 Author Report Share Posted June 1, 2012 Thanks again for the feedback. I will go with the 3.73 and taller tires. If I do that it should drop the RPMs down by a total of a little over 350 at 55. Thats pretty decent. Going from 2800 to 2450 would be comfortable I think. A rear end with a 3.55 ratio was what I was going for but I cant pass up FREE. Greg. I couldnt get your calculators to work on this computer for some reason so I found another site with the same. Nice thing is both calculators were there towards the bottom of the page. There were some other cool calcs there as well. http://www.rocky-road.com/calculator.html Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted June 1, 2012 Report Share Posted June 1, 2012 not sure but am thinking you are running stock flattie..do you intend to stick with the flat head? and question two, are you entertaining a 5 speed for later? these are consideration that will play a big role in the ultimate rear end selection Quote Link to comment Share on other sites More sharing options...
yourpc48 Posted June 1, 2012 Author Report Share Posted June 1, 2012 not sure but am thinking you are running stock flattie..do you intend to stick with the flat head? and question two, are you entertaining a 5 speed for later? these are consideration that will play a big role in the ultimate rear end selection Yes on the stock flatty unless it dies (trying to avoid that) I might be adding an intake with a little more CFM if you know what I mean. also am going to change to electronic ignition. Maybe dual exhaust at some point but not right away. No change in the transmission expected unless it dies. Right now I am thinking 3.27 with short tires or 3.73 with tall tires. Thanks Quote Link to comment Share on other sites More sharing options...
Robert Horne Posted June 2, 2012 Report Share Posted June 2, 2012 If you are not happy with the setup you decide to use, you can always change the gears in the rear..... Quote Link to comment Share on other sites More sharing options...
yourpc48 Posted June 2, 2012 Author Report Share Posted June 2, 2012 If you are not happy with the setup you decide to use, you can always change the gears in the rear..... Yep. And I may do that once it is set up. I had thought about that as well. Wanted to try to avoid that but if it happens.... Oh well. I should be getting the rear end this weekend or early next week. Ill have to save up a little and then get it all installed with lots of pictures of the "step by steps." It seems to me that 25 years ago when I sold my D24 (it was really nice) I sold it because it was too slow and wouldnt hold a hill on the E-brake. All things as I had gotten out of my teens I learned can be fixed with little effort. Quote Link to comment Share on other sites More sharing options...
FESTER60 Posted June 2, 2012 Report Share Posted June 2, 2012 I am very interested in this thread as I will be swapping my stock rear end for an Explorer unit also. Here's another angle. I have my 318/904 installed. What would be the best gears for that setup? I am not looking for any quick starts, just a low rpm for good mileage at 55 or so. Quote Link to comment Share on other sites More sharing options...
yourpc48 Posted June 2, 2012 Author Report Share Posted June 2, 2012 (edited) I am very interested in this thread as I will be swapping my stock rear end for an Explorer unit also. Here's another angle. I have my 318/904 installed. What would be the best gears for that setup? I am not looking for any quick starts, just a low rpm for good mileage at 55 or so. That would depend on the build of your engine and gear ratios and spread of the gears in the trans OH and tire size. Im not familiar with the trans in question. Do you know what model your engine combo came out of? If you do then look at that rigs gear ratio and get it close to that if the rig weighs less than your car then put in the same or a slightly lower ratio. If its the same or heavier then put in a gear ratio the same or higher. A general all around cruiser could easily be a 3.27 with V8 and auto if you are doing a lot of highway driving. Most of the 70s and 80s cars had 2.73s or 3.08s . My 36 ford PU had 3.08s and an olds rear end if I remember correctly but it only weighed 2500 lbs. Our cars weigh in at about 4000 with people in them. Lots of in town driving? well 3.27 or even 3.55 might be better. I dont know if it goes any further below 3.27. If you go too high a gear ratio and you have a little umph to your engine then you might load up too much with lots of in town driving you also will not have near the power you have with the original 4.11s. Happy medium might be a 3.55. Ultimately its your decision but if you are used to the torquey (I think I just made up a word) umph of the 4.11ish ratio you probably have now, then I wouldnt go below a 3.55 If you dont mind the loss of a little more umph for a little more milage than the 3.55 would give you then go up to the 3.27. You will find you get much better highway milage but suffer just a little around town. If you want to increase your milage just a little and not notice a power difference then go with the 3.73 SO really you should figure out how much you drive in or out of town. I need to travel a lot on the highway to different towns close by. I am going to a parade and show tomorrow in a town 20 miles from me and I dont think much about it at all. 20 to 30 miles is the normal for many of my computer service calls when I do out of town services. WOW you got me thinking a little bit about lotsa stuff. Now my head hurts. Edited June 2, 2012 by yourpc48 Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted June 2, 2012 Report Share Posted June 2, 2012 the last of the RWD 318/904 combo's as offered in the Chrysler 5th Avenue carried a 2.32 rear ratio..these puppies cruise at 80 MPH without any problem all day long..they no rocket off the line but easily accelerate to traffic speed..so if it truly economical operation you looking for...this was it.. Quote Link to comment Share on other sites More sharing options...
oldodge41 Posted June 2, 2012 Report Share Posted June 2, 2012 I had a Plymouth Duster with the 318/904 combo. It had the 2.90 something rear and the then had 3.23 gears. The 3.23 was great for playing and traveling. The other was great for travel but not so much fun to play with. I am running an Explorer rear in my '41 Dodge with a '48 Dodge 230. It has 3.27 gears in it and the more I drive it the more I like it. Keep in mind I have fluid drive. My travel is a combo of in town and secondary two lane roads around Central PA. Never flat land for long. My first gear seems low enough and my high gear is high enough. I wish I had two gears between them instead of just one but that was the reason for 4,5,6 speeds in the first place. Quote Link to comment Share on other sites More sharing options...
yourpc48 Posted June 2, 2012 Author Report Share Posted June 2, 2012 Well heres how it all starts for that rear end swap! Thats right! Can everyone say DONOR?????? The car is at my house but we need to get the rig up on a car trailer first so we can take it to the scrap yard when we are done. There will be other parts scavenged as well. Quote Link to comment Share on other sites More sharing options...
RobertKB Posted June 2, 2012 Report Share Posted June 2, 2012 Unless it is the rear disc brakes you want, I am not sure why you are swapping out the entire rear end. Chrysler made a 3.73 differential for the cars in the early 50's. The axles have finer splines on them so you have to swap over a few other pieces in the differential but it's got to be a lot easier and less work than changing out everything. Heck, I've got a couple of them sitting around doing nothing in some parts cars. Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted June 3, 2012 Report Share Posted June 3, 2012 I personally feelswapping over for better gears and better brakes be they disc or floating shoe without taper axle is much better improvement all around...so if there is that NEED to change..change for the better.. Quote Link to comment Share on other sites More sharing options...
yourpc48 Posted June 3, 2012 Author Report Share Posted June 3, 2012 Thank you for the suggestion on the rear end. I really do appreciate it. I might have tried something like that if I knew what parts to change out etc. but for me the Explorer swap is probably a better choice. Im swapping for several reasons. 1 Its a free part. It was even dropped off in my front yard. Doesnt get much better than that. 2 it gets rid of that funny drive shaft. True if I wanted I could just change the drive shaft but why would I do just that unless I wanted it original (which it would not be) 3 changing the rear end to something modern gives me better brakes regardless if its drum or disk. 4 wheel disk is cool though. 4 The newer rear gives me the ability to walk into the parts store and say "I need blah blah blah for a 2000 Ford Explorer" and chances are really really good that I will walk out of the store with the part in my hand. 5 The Ford 8.8 is a pretty beefy rear end. Now I know of a 58 Ford wagon I could have gotten a 9 inch out of but there again I would be working with something 54 years old. So you might say why dont you just change the body onto a new chasis? Well, in my opinion that is even more work than the little mods Im doing to the car. I can appreciate the ease in swapping to something that will bolt right in but not if I still have to wait for parts if I wear them out or break them. I drive the car almost every day. Heck I put over 100 miles on it today with a parade and car show in the town 20 miles south of me this morning and riding in the sand dunes with friends 30 miles north of us this evening. I want the best of both worlds. Old car with easy to find parts for those things that wear out the quickest. I did the conversion to front disk first. Now comes the rear end. Then the steering or maybe the distributor (someone answered my craigslist ad today in the wanted section). Once all these things are done I should have a very (Every day) drivable car. Quote Link to comment Share on other sites More sharing options...
falconvan Posted June 3, 2012 Report Share Posted June 3, 2012 Four wheel disc is going to be a great addition and like you said, readily available at any parts store. Quote Link to comment Share on other sites More sharing options...
rumble48 Posted June 3, 2012 Report Share Posted June 3, 2012 I personally feelswapping over for better gears and better brakes be they disc or floating shoe without taper axle is much better improvement all around...so if there is that NEED to change..change for the better.. x2.... I have used the 8.8 rear in swaps in the past, and found them to be a solid axle.... good luck... Quote Link to comment Share on other sites More sharing options...
yourpc48 Posted June 4, 2012 Author Report Share Posted June 4, 2012 x2.... I have used the 8.8 rear in swaps in the past, and found them to be a solid axle.... good luck... Hey. Your in Merlin? Your not too far from me. Im in Coos Bay. Another member is in the Roseburg area. Quote Link to comment Share on other sites More sharing options...
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