hey gusy i was wondering somethign about the ford 8in rear end and the for 9 inch rear end. what is the max hp for the 8 and how much more sturdy is the 9 if at all? and what would i have to do to replace my 8 with a 9? or woudl it be better to go with an 8.8? or would an 8.8 fit? i have a 67 stang. and info on each of the rear ends would be nice.. thanks in advance
ford 8in ford 9 in and ford 8.8 in
- Thread starter Damein17
- Start date
302 coupe
Founding Member
the 8" is limited to about 300 hp reliably. Gear selection is scarcer than for the 8.8 or 9". Its kinda the bare minimum for a V8.
The 8.8 is a good rear, there is a good selection of gears, and lots of aftermarket support thanks to the 5.0 guys. Aftermarket axles, limited slips/trac-loks/posi's, and lockers are readily avaliable. Some came with disc brakes too. However, most 8.8's came from cars with a totally different rear suspension design. This means you'll have to cut off the factory brackets and weld on new perches for your leaf springs. 8.8's can also be found in explorers, rangers, F150's, etc. These all have leaf springs, but the perches are too far apart so you still have to install new ones. In addition to all that, there are many different lengths and several different axle configurations. The 8.8 is strong enough and can be made to fit properly, but it can get involved.
Now the 9", regarded as the rear end of choice for racers and rodders for a long time. Gear swaps are easy, wide selecion of gear ratios, an assortment of aftermarket performance axles, and a wide selection of traction devices(trac-loks, lockers, etc.). This wide selection of parts means that parts are cheap and readily available. Most 9" housings are too wide, but there are some that are the right length to fit your car. Check out ultrastang.com for more info on the 9."
The 8.8 is a good rear, there is a good selection of gears, and lots of aftermarket support thanks to the 5.0 guys. Aftermarket axles, limited slips/trac-loks/posi's, and lockers are readily avaliable. Some came with disc brakes too. However, most 8.8's came from cars with a totally different rear suspension design. This means you'll have to cut off the factory brackets and weld on new perches for your leaf springs. 8.8's can also be found in explorers, rangers, F150's, etc. These all have leaf springs, but the perches are too far apart so you still have to install new ones. In addition to all that, there are many different lengths and several different axle configurations. The 8.8 is strong enough and can be made to fit properly, but it can get involved.
Now the 9", regarded as the rear end of choice for racers and rodders for a long time. Gear swaps are easy, wide selecion of gear ratios, an assortment of aftermarket performance axles, and a wide selection of traction devices(trac-loks, lockers, etc.). This wide selection of parts means that parts are cheap and readily available. Most 9" housings are too wide, but there are some that are the right length to fit your car. Check out ultrastang.com for more info on the 9."
brianj5600
Active Member
I have about $200 in my 8.8. Posi, 5-lug, drum brakes. Fox rears are the right length for a '67 and axles from a 4cyl ranger driver side 7.5 rear are the same length, but 5 lug. Cutting brackets off is a pita, but my time is cheap. There is no shortage of 8 second cars with 8.8s at a FFW or NMCA race so I would not worry about their potential.
HP capacity has alot to do with weight, traction, auto or clutch etc. What is your plan and someone can give an opinion on which might be best for you.
HP capacity has alot to do with weight, traction, auto or clutch etc. What is your plan and someone can give an opinion on which might be best for you.
As for axle selection for the 8", this would be the same as the 9". They share the same axles. Ditto for the 8.8 and 7.5. The only real handicap for an 8" is gear selection. Posi units are relatively plentiful, if you're shopping for a new unit. The 8.8's strength capability lies somewhere between the 8" and 9". If you DO do an 8.8 swap, I highly recommend using 9" style housing ends to eliminate the "C" clips when you have it narrowed.
302 coupe
Founding Member
the 8" is limited to 28 spline axles, so performance axle selection is limited. However, I've never damaged a 28 spline axle, but I have destroyed the differential on 3 different 8" rears.
302 coupe
Founding Member
I think all 8" rears came from the factory with five lugs. I know some pintos came with 8" rears, maybe they were 4 lug, I dunno. Are you sure you have a 8"? Could you post a pic of what you have?
V6 Pintos and a few Mustang IIs came with an 8" rear.302 coupe said:
I like the 8.8 better than the 9". The 9" has the benefit of more gear ratios and you can have pumpkins sitting around with alternate gears.
The 8.8 takes a slight bit less hp to turn, so you can put more power to the ground. The 8.8 pinion is also much stronger than the 9". You can have 9" axle ends welded on to get rid of the c clips.
I have put a few 8.8s into early Mustangs, If you are a competent fabricator, or have access to somebody, it is an easy swap.
brianj5600
Active Member
The run of the mill 9" is not w/o weakness as well. 8.8 and 9" are not that far apart in strength unless it is an "n" case and daytona pinion support. If you are making serious hp and have traction, you can't just bolt in ANY old rear end out of the junkyard.
