Best way to change gears and ad posi

madstang78 · 01-31-2013, 06:29 AM

My car has the 8" rear and is 5lug. I have already rebuilt the brakes on it. I was going to put a fox body rear end in it but I am looking at other options know as to the best way to change my gear ratio and get posi.

I could get a new 8" third member but they seem to be about 800-1000 bucks online? This seems to be the easiest way to go about it.

Or I could try and find a 9" unit in working order but I do not know if my drum backing plates and fresh drum brakes will bolt on

Or so the fox rear end swap. But most of those are 4 lug and there is a fair amount of work to be done for that swap.

I do not like the explorer offset idea.

Anyone have opinions.

Lee12609 · 01-31-2013, 06:47 AM

You can get a posi for the 8" and gears and not have to worry about brakes or modifying anything.

65since88 · 01-31-2013, 06:48 AM

I got a used set of fomoco 3.50 gear set at a swap meet for 100$ and a True/Trac from Summit under 500$ and did it myself with a new bearing kit and the Ford manual. Once you get the right pinion shim in there its gravy with no side shims in there and the book in front of you. You do need access to a press to install side bearings and a brass drift.

LastDeadLast · 01-31-2013, 07:19 AM

I had a local shop add a truetrac to my existing third member.. I already had 3.89 gears or I would've done that too.

Truetrac's are awesome BTW, truly a zero maintenance item.

-Shannon

csouther · 01-31-2013, 04:45 PM

Its not hard to get a detroit locker or truetrack installed in there. If you like your 8" and brakes then just shop around for the locker and install it yourself. As mentioned before, its not a very hard install and doesn't require special tools.

cmefly · 01-31-2013, 05:14 PM

Your 8" rear brakes will fit a 9" small bearing housing. If you stay with the stock length housing your 28 Spline axles will also fit.

ajzride · 01-31-2013, 07:09 PM

Used gears can be had under $100. You could consider a lock-right. The price is certainly right.

Powertrax 1810-LR Lock-Right Locker | Ford 8"

BiffStroganoffsky · 01-31-2013, 07:14 PM

Currie's 9+ 8" posi unit is ~$450 from Summit - or - you can call Currie and have them price match.

madstang78 · 02-04-2013, 08:47 AM

Posi units seem to be like you guys stated at around 4-500. And gears are around 150-200. Plus bearings install kit etc. maybe spending 850 on a third member is not such a bad deal after all. It just so much easier than making the fox body rear end I have here work. My car is already 5 lug