How much hp can a 7.5 handle?
- Thread starter 85 B Regal
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85 B Regal said:
Yeah you'll be fine with your 7.5.
85olds said:
I like the TKO's, but i'm gonna upgrade my T5 with a internals kit from Gforce Transmissions. For about $750 the kit will allow a T5 to handle about 600+ hp with ease. Gforce builds 900 HP complete competition T5s. Yet the lure of the T56 is calling me also. Gforce has improved internals for that too.
jetsetw31 said:
The G force gears are cut with less of a helical cut but to hold 600 hp you'll need to upgrade the casing. The force from the gears will twist the stock casing and that's when the transmission will explode no matter what gear set you have. Get a good hurst shifter and that will help save the transmission. The stock shifter give you sloppy shifts and that could damage the tramsission
My '87 had the 7.5 behind the 455 for years and I've had one behind the 403 in the '81 as well. It's not the HP that will kill them but the torque, weight and traction.
Of course both of those rears were rebuilt with aftermarket parts (Auburn limited slip, Richmond gears, etc.). I also never put slicks or drag radials on the one behind the 455.
Now the 7.5 behind the 403 has new axles and a rear support girdle/cover. It has been fine with drag radials and beating the snot out of it.
With a mostly stock 350 your not going to hurt a 7.5.
Of course both of those rears were rebuilt with aftermarket parts (Auburn limited slip, Richmond gears, etc.). I also never put slicks or drag radials on the one behind the 455.
Now the 7.5 behind the 403 has new axles and a rear support girdle/cover. It has been fine with drag radials and beating the snot out of it.
With a mostly stock 350 your not going to hurt a 7.5.
Greetings Guys; I flash back to 91(?) when Car & Driver did a test on a 383 Lingenfelter Camaro with 410 Lbs ft of torque & a 5 speed manual. They broke the 7.5 the first time that they dropped the clutch. That's when I started looking for an 8.5". My first gen (1985-94) 406 incher only made estimated 400 HP & 425 Lbs torque, and I didn't break the 7.5". But in 1995 when I built gen II 406" I dynoed (433 HP) it and knew that the 7.5" time was short. So in 98 I found a 8.5" and sold the 7.5" posi before I broke it. And to stop flex I had 2 gussets per side welded form the center section to the control arm mount and from the mount outboard. I've made about 25 passes with DOT slicks with no problems. Other than one of the Buick axles wore out. I should mention that a fresh 406"er gen III (475 HP - 500+ Lbs ft est) was placed under the hood in 2004. And around 15 of those 25 passes were with the stronger engine. So somewhere around 400 + Lbs of torque you should be careful, no slicks or dumping the clutch. My .02 cents Bob Jr.
PS: I'll post a picture of the 8.5" over on my for sale post in the near future.
PS: I'll post a picture of the 8.5" over on my for sale post in the near future.
Everyone has a story. Here's mine. I beat the crap out of the 7.5" in my cutlass, which has 3.73 gears and an eaton posi. My cutlass makes close to 400hp and 450+ ft lbs of torque, and i had a Muncie in it for a while. Never had an issue, and like i said, i'm never nice to it lol.
My malibu still has the stock 7.5 rear, probably 2.73's, and now has a big block. I've been beating it pretty hard over the last week and haven't has an issue yet (knock on wood.)
Needless to say, I'm expecting one of them to blow up some time, and when it does, it will be replaced with at least an 8.5 if not a 12 bolt.
My malibu still has the stock 7.5 rear, probably 2.73's, and now has a big block. I've been beating it pretty hard over the last week and haven't has an issue yet (knock on wood.)
Needless to say, I'm expecting one of them to blow up some time, and when it does, it will be replaced with at least an 8.5 if not a 12 bolt.
FE3X CLONE said:
X2. Yet, a rebuilt 7.5 with stronger aftermarket parts can handle 400+ hp. Above that, the case is the weakness. I saw the carnage of a 7.5 with high dollar parts ie. nothing stock left but the case. 7.6 gear set, billet pinion, billet caps, and a preload cover. he cracked the case on a 9 second run. And it wasn't a heavy G body, it was a 85 f body. Basically the same case.
pontiacgp said:
G force told me themselves that the stock case is good to 600 hp with their internals. There is a bolt on ring that will stop the rear bearing from losing shape but that about it. X2 on the shifter. I need to hurry and get this kit, because every year the price goes up. When I first spoke to them the kit was $500.
I stand corrected, the kit is already over $1200, But still worth it to me.
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