400 and 7.5" rearend

[85montemj]

my dad used to race at a 3/8 mile track in a 70's chevelle with a 400 in it. the car is long gone but the engine is still in my grandpa's garage. its a 400 small block bored .030 over, bluebrinted and balanced, and the heads are ground down( im not sure how much). would my 7.5" hold up to this?

 

[RITTER]

All depends on how you plan on driving it. If you are going to drag racing with the car and launching it from a stop as hard as it will, then it will not hold up for long. If you just plan on driving the car and cruising around town, it will hold up for quite a while.

 

[dogsht]

With a good converter & slicks its only a matter of time. Regular radials & some spirited driving it should last a long time.

 

[Onebadbowtie86]

It will last alot longer then you think. I run an afr headed, roller cammed 383 with a t56 transmission. I have the stock 3:73 posi rear with 180k miles on it. I beat the snot out of my car and run 26x10.50 ET streets at the track and dump the clutch at 4k rpms and havnt had a problem.

 

[85montemj]

ok sounds good! maybe if i come across a nice and cheap 8.5" i'll get in the future

 

[80Maliboo]

It will last alot longer then you think. I run an afr headed, roller cammed 383 with a t56 transmission. I have the stock 3:73 posi rear with 180k miles on it. I beat the snot out of my car and run 26x10.50 ET streets at the track and dump the clutch at 4k rpms and havnt had a problem.

What 60' do you run?

 

[jimmyp618]

It will last alot longer then you think. I run an afr headed, roller cammed 383 with a t56 transmission. I have the stock 3:73 posi rear with 180k miles on it. I beat the snot out of my car and run 26x10.50 ET streets at the track and dump the clutch at 4k rpms and havnt had a problem.

I agree. Ive pulled the left front off a few times w/ mine . All i did was upgrade to moser gn axles. 3000 stall w over 575 ft pnds of torque at about 465 hp. Its just a chance ya take but i will run mine til it goes just to see what its limits are. I could buy about 20 or so 7 5/8 diffs 3 series carriers at a JY for the cost of a good 9" or gn rear which ive seen them blow up as well.

 

[Bonnewagon]

I ran a Pontiac 400 for many years with a 7.5" rear, never no trouble. The trick is having decent gears so you aren't straining the rear. As stated, it will last if you respect it for what it is.

 

[jrm81bu]

It will last alot longer then you think. I run an afr headed, roller cammed 383 with a t56 transmission. I have the stock 3:73 posi rear with 180k miles on it. I beat the snot out of my car and run 26x10.50 ET streets at the track and dump the clutch at 4k rpms and havnt had a problem.

I agree. Ive pulled the left front off a few times w/ mine . All i did was upgrade to moser gn axles. 3000 stall w over 575 ft pnds of torque at about 465 hp. Its just a chance ya take but i will run mine til it goes just to see what its limits are. I could buy about 20 or so 7 5/8 diffs 3 series carriers at a JY for the cost of a good 9" or gn rear which ive seen them blow up as well.

Just remember to add in the cost for new tires and quarter panel repair when the tire and axle comes out, shreds the tire, and crushes the quarter. And any other damage that may occur, with hopefully no-one getting hurt. That said, I'm sure people have had good luck with them, but its gonna go eventually. And yes I still run mine, can't afford anything else at the moment. And I've also broken many of them too.

 

[patmckinneyracing]

Mine in my malibu came out of a 86' monte ss, so technically its a 7.625 rear end. I had a reputable local differential shop rebuild the rear end, mainly new seals and that was about it. He looked through said it was very clean and has the auburn posi. About 6 months later, one of the teeth chipped off the pinion ring, so I had the same guy go into again and put in new yukon gears and have never had a problem since.

I run a sbc 350 making about 380hp/425lb and have laid my foot into it plenty of times. Left 25ft double strips showing the ricers what a real burnout was, cause none of them could do it even though they tried.