9" 8" pros cons

daniel_old · April 14, 2008 at 11:03 PM

i was wondering is a 9" really that great of a rear end to use in a 65 mustang? i have a 302 with about 350 hp and wondering if i should stay with 9" or go to the lighter 8".

SixT5HiPo · April 14, 2008 at 11:39 PM

The Ford 9" rear axle is legendary for it's strength and durability, period.

oscart_old · April 15, 2008 at 7:16 AM

Unless you plan on drag racing the car, the 8" is plenty strong. You will not break this unit with radial street tires. Plus, it is a lighter unit which reduces the unsprung weight. Traction lok units are available for the 8" as well. Unless the 9" was original to the car, I would stick with the 8" and put my money elsewhere.

RPM_old · April 17, 2008 at 3:46 PM

I disagree as it sounds like he has a little hp and with that being said most people who build hp don't baby their cars.Go with a good 9 inch with 31 spline axles and traction lock posi as you'll save money.If you did the same thing with the 8 inch you'll spend more money as most of that stuff is high dollar!

hipo_p51_old · April 17, 2008 at 7:00 PM

rpm is right! wouldnt you rather say you have 9 inches instead of 8?

66gtk · April 17, 2008 at 8:13 PM

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>

rpm is right! wouldnt you rather say you have 9 inches instead of 8?

That's too good!<img src=images/icon_smile_big.gif border=0 align=middle>

oscart_old · April 18, 2008 at 5:09 PM

If you want to just tell people you have a 9" then go ahead and install one. With street tire, no way will you brake a decent 8". I used to race a fellow in a 1967 Cougar (slicks) who went from a modified 289 to a built 351W and finally to a 460. He only changed to a 9" when he went to to the big block. He was running low 11's in the quarter with nitrous and a "mild" 289. Sorry, but you just won't brake the 8" with street tires. You just can't produce enough torque with street tires to bust that ring and pinion or the axles for that matter. And 350 HP in todays world is considered mild.

If you are concerned about breaking parts first:

-replace your u-joints with solid units

-upgrade to a race driveshaft and yoke

-install a driveshaft safet loop.

Once this is done, if you want, go for the 9". Having a drive shaft rattle around lose under the car or worse can really ruin your day.

dunc289_old · April 18, 2008 at 8:08 PM

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>

rpm is right! wouldnt you rather say you have 9 inches instead of 8?

<hr height=1 noshade id=quote></BLOCKQUOTE id=quote> ooooohhhhh..... you are bad, the nine inch really will wind up the same price, bullet proof, and bragging rights!!<img src=images/icon_smile_big.gif border=0 align=middle>

hipo_p51_old · April 19, 2008 at 12:27 PM

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>

rpm is right! wouldnt you rather say you have 9 inches instead of 8?

<hr height=1 noshade id=quote></BLOCKQUOTE id=quote> ooooohhhhh..... you are bad, the nine inch really will wind up the same price, bullet proof, and bragging rights!!<img src=images/icon_smile_big.gif border=0 align=middle>

amen brother!

daniel_old · April 29, 2008 at 12:22 AM

i ended up going with the 9 inch thanks for the replies

Participate now!