I found a 78 Mustang with axle code 7. having 3:40 gears non locking. Is this going to be good ? I have a 250 eng. automatic. 8 inch rear. 2:79 gears. I don't understand what the non locking means? I couldn't get to see the tag being that its sitting on the ground with a 1/2 a ton of car over it. The wreaker wanted $150.00 Can. for the the hole axle. Is this a good price to pay for the gears? thanks for the help.
you can buy a new set of gears from Summit for $150. i think it's a bit high myself considering you just need the gears, and it's "non-locking" (which means it's an open carrier and ISNT a posi and/or traction-lok unit)
I have to agree..it does sound a bit expensive! But then they are getting tougher to find(here anyway) and it is a drop in unit so it is ready to go now... I would see if they can drop the price a little...it that the whole rear or just the centre section?
150 isnt that bad of a price. sure a new gear set costs that much but you still have to pay to have it installed. you can put your third member back in to the m2 housing and sell if for a few bucks on craigs list.
It seems like a decent deal. If you bought the gears by themselves thats $150+$50 for a basic rebuild kit and probaly $100 or so to set them up unless you have a friend who knows how
They want to sell it as the whole rear. When you say it is a drop in unit. do you mean I just have to swap in the center section? I'm always learning more about this stuff, and I don't even know what the gears look like. but I figure if I have something here, now, that I can use, maybe I should pick it up.
Yup..if the Mustang has an 8" also...you can just pull the axles and then just exchange the centre sections...for a whole rear $150 is not out of line
O-kay, I gess the 3:40 would be an upgrade from the stock gears. now I'll have to find $150 to pay the man. It may have to wait a little while. Thank you all for the help? How much more horsepower would I get out of it?
Well if it's an 8" rear... It would be at least as strong as stock, and there are people here who run lots of power through 8" rearends. Some people will tell you it's junk because it's not a 9", I but I don't recall reading a lot of posts about shattering ring gears here on the MMB. Now when I was on Camaro and S10 forums, it was different. I personally destroyed 4 GM 10-bolt rearends using the unholy brute force of a mostly stock 305.
you will get no horse power from the gear change. you get torque multiplecation from the ratio change. if you put it on a chassie dyno usually the hp drops when you goto a numaricly higher gear. thats been a way of cheating chassie dyno numbers.
Ah, guess I misread the question. Right. Gear change doesn't give you horsepower, it gives you acceleration at the low end at the expense of top end speed.
Is there a real benifit to swaping the gears? Would I save money on gas? I see the 3:55 with the tlok are popular. Would the 3:40 be real different? Are the 3:55 with the tlok rare? to find on a Mustang 2?
You would be unlikely to tell much difference between 3.40 and 3.55. To me, yes there's a benefit! Your car will certainly "feel" faster and more powerful, because your engine will be revving higher at lower speeds. Your acceleration will improve. Track times will likely improve if you're into that sort of thing. Gas mileage will not improve though. And your potential top speed will decrease. I think Trac-lock 8" rears are not terribly uncommon in Pinto wagons and they can be found in a few Mustang II's. For me though, the MII's and Pinto wagons are what's getting hard to find.
