so my situation is, i want a limited slip rear in my 70 maverick when i do this 347 engine updrade. i know i can use an explorer rear and thats fine, BUT i want the 2.79 gears. so which will be cheaper? a new complete rear that is the way i want it or can i go cheaper still using the explorer rear if i change the ratio on it with consideration to the shortening of one side? if a new rear costs only a little more than the re-geared explorer rear i would also consider that as long as the price isnt too much higher.i just want this done right and be strong. what are my options here? EDIT: i cant believe i forgot, but i do have a 5 lug rear from another maverick in the shed. it does have the 2.79 gears. can i just replace the pumpkin with an lsd version? is this strong enough for a 400hp engine?
I'd ditch those gears myself and the 8"will hold awhile but their not super strong. If you plan on going with a larger tire I'd go as least a 3.25 gear.
I'm glad you mentioned tire height. I didn't even consider that. Maybe a 3.00-3.25 would be better. Ty!! EDIT: until i get the new wheels and tires on there im not exactly sure of tire height. but based off just a few ive seen and the look i want vs stock tire height, its looking like i would need a 3.55 gear to have a good rpm at 70 mph (2200). i suppose ill have to just get to the tire selection point first, measure tire height, then talk to gear vendors about what they recommend, but is looking like 3.55. so it does look like the explorer rear with 3.55 gears
You originally considered 2.79 gears with a .78 overdrive that would have given you the equivalent of 2.18 gears. Why?
Well that's kinda the point. I've got a lot to learn. I'm now thinking a 3:55 rear. What's your opinion on that? The only thing I'm not sure of atm for rpm consideration is tire height.
You have to look at the whole setup; engine, trans, rear, tire diameter, and how you're gonna use the car. When cruising in overdrive you don't want to lug the engine (bearings don't like that, ever wonder why so many T5/5.0 Mustangs needed bearings replaced?) and you want to be in the cam's rpm operating range for engine efficiency. That 2.18 final drive would have a powerful, aerodynamic car going way above any legal speed limit but I'm not so sure it would work too well in a 347 Maverick. But I've been wrong before.....
So do you think turning 2500-2800 rpm at 70mph would be fine? This is the cruise speed I usually drive at. Is at least like to hit 70 and not worry about high rpms.
See I'm thinking 3:55 gear too after playing around with a gear ratio calculator earlier. I'll input that tire size tomorrow and see how that goes.
The Explorer rear comes with a larger ring gear (stronger), every one I have seen is limited slip (but heard rumors that I doubted of some not LS), 31 spline axles instead of 28, and disc brakes. It has a lot going for it. I think you will find a 3.55 more often in a 2 door Sport. 3.73 gears are common too, and may be found more often in 4 doors Explorers. The good news is that most will still have their axle tags that will tell you the ratio. You will have to redo the spring perches. If you use an 8 inch rear, many will bolt in. I would look for another housing that is 1 inch wider to get the wheels away from the springs. Late 60s Falcon is one that comes to mind. You are probably looking at spending at least $800 on a set up center section with the gear and limited slip. That number comes from a common eBay vendor that I last noticed a couple years ago. If you want disc brakes, there is the Crown Vic brake conversion. Neither one will be cheap.
I personally wouldn't want to go any higher than that. Overdrive would get you even closer to 2000 rpm but you don't want to be running a cam that has a powerband that starts at 3000 rpm.
ok i have it all figured out now. once i get the tire size i want ill measure the height then decide with the help of some math as to what gear ill get for the rear. im shooting for about 2200rpm at 70 mph. with that hp and torque ill have this should be good to go.
Every engine has its own personally. I get the best mpg at 3300 rpm/72 mph in my 60 Falcon (19.75 mpg). I get about 15 mpg at 2300-2500
