8" Rear Behind 428 on the Street--Will it Live?

[410bruce]

Relatively light '67 Cougar, street tires, 4-speed.
Will the stock 8" rear live or should I be looking for a 9"?

I realize how it's driven will dictate the outcome but outside of 5000 RPM clutch drops, I would think it would last--even with a little abuse thrown at it. Am I wrong? 

[SSdynosaur]

I seriously doubt it, if that were the case Ford would have tried. The street rod folks love them but in most of their applications GVW is less than 3000 lbs.. The other issue is cost; building both from scratch, similarly equipped the nine inch will only command about a 25% premium over the eight inch. If you elect the eight inch be sure to build into a, substantially stronger, '67-up case.

[Royce]

Depends almost entirely on how well your tires hook up.. With sticky tires a 428 probably exceeds the toque limit on an 8 inch

[mike7570]

8” probably won’t last long, a friend of mine broke his with a 302 and M/T ET streets.
It had decent parts in it and the 302 was a pump gas engine.

[Rory428]

Considering Ford felt the need to install a 9" in any Mustang or Cougar with over 230 HP, they must have thought the 8" was inadequate. Unless you never drove that 428 on dry roads, I wouldn`t waste any money on a 8", especially with a 428 and a 4 speed!

[Tommy-T]

Jumping in the way-back machine, around 1980, I had a '63 Falcon sprint that I street raced 3 nights a week at least. It had a "hot" 289 and a C4 with a manual valve body and an 8" with a mini-spool with 4.62 gears. The rear tires were 29" tall L78-15 Caldwell soft rubber re-caps. They tucked up nice in the Falcon wheel wells as they were fairly narrow but tall.

That car ran mid-low 13's in full street trim. Hooked and booked. You could flat foot the throttle and the tires would spin maybe 1 revolution and then you were gone. I never hurt the 8" ever. I think the soft low end torque of the 289 coupled with no wheel hop and automatic trans kept it pretty safe. I regularly whupped up on big block muscle cars that were running the requisite T/A radials of the day or Positraction Torque Twister bias plys that were popular here in the Los Angeles area.

That said, I have destroyed more than 1 2 spider 9" Fords with relatively stock 390 Fords motors on regular street tires.

Your 8" will live fine if you drive like grandma. If it hooks or hops you'll bust it. You already knew this when you asked.

Save until you can do your 9" right. Custom width housing so you can get maximum tread width in your wheel well, good case with TruTrack or Detroit, and a Cal Tracks set up. Waste of time and money building a 500 horsepower motor if you can't hook it.
 

[wayne]

I would say not long i had a 67 fairlane with a 289 f 4b intake factory hyd cam headers accel dist. Not much but it run good had a 8 in with 3.50 gears m/t street tires.Came out at 3500 rpm the pinion broke out the front of the case broke the tail shaft housing and the case on the top loader.It had slapper bars and did not wheel hop.I still hear about it when some of the old bunch try to relive the old days.

[frnkeore]

I agree on the 8" not lasting long.

A good friend, here in my area, has broken at least 2 with not to hot 302's.

Wheel hop is a real killer with that 8".

The 9" in my factory, '65, K code, 2+2, survived a bunch of wheel hop, with 10" rear tires. All though similar  designs, the 8" doesn't seem to be nearly as strong.

[machoneman]

I say, drive it until it breaks!

Now, that said, I'd not spend a dime on your current 8" rear so if it's runable, use it.

[shady]

I had an 8" 3:90 open behind a boss 302 4 speed that survived at least a hundred of 4k clutch dumps. Had traction bars set-up with preload for both wheels to spin. Never broke it.

[FERoadster]

Bruce: I've got a couple of 9" rear axles that would come very close to fitting your Cougar. They are 57-59  Ford housings and one 58 Edsel housing. I've got the axles as well.
Nice part is I'm only about 120 miles north of you on Hwy 101, Brookings Or.  I'd go $120 for the housing and a set of axles.  Don't want to ship.
I will not sell the true 57 Ford housings that don't have the dimples.

Richard >>> FERoadster

[427LX]

Well I ran several high 12's in my 85 Mustang with the weenie 7.5 rear 5 spd and slicks.  Later put a 9 under it but didn't break the 7.5

[allrightmike]

Had a '63 Fairlane 260 4 speed 4 barrel, drive it to Daytona from MI to see the 500 race, must have been around '66. Showing off in front of the motel spinning the tires in the sand and hit clean pavement, spit the pinion right out the front of the case, didn't even break the u-joint. Paid way too much for a new pig and installed it at the motel. Seems I remember we used the motel's towels for shop rags and they were not very proud of us for that!

[Joe-JDC]

I had a '66 Fairlane 289 4 speed with 3.50 gears and posi in 8" rear that I drove with over 300 hp at the wheels.  Installed a 358W 4V and headers, ported heads, intake, etc.  Ran it hard for several years and never an issue with the 8" rear.  Surprised a lot of "hot" mustangs with that 351 and 4 speed.  Joe-JDC

[wayne]

I have a 84 mustang gt with a good little small block and have run it hard for 15 yrs and has the same t5 and 7.5 (3.73) gear never any slicks