6 to 8 swap
Thread Starter
Joined: Oct 2007
Posts: 1
6 to 8 swap
hey guys i'm new to the forum and i'm looking for some advice. i drive a 1970 250 ci straight 6 mustang and thinking about upgrading to an 8. will the original rear end on this car handle a mild V8? what about the transmission?
3rd Gear Member
Joined: Jun 2006
Posts: 621
From: California
RE: 6 to 8 swap
The rearend may handle a stock v-8, but since you're doign teh swap, I assume you want more performance. You can be confident if you witch to an 8 or 9 inch rearend. Whatever transmission you have now should do fine on the V-8. Since you'll be doing a swap, it would be a good idea to get the tranny rebuilt/put in a transmission of yoru choice.
4th Gear Member
Joined: Oct 2006
Posts: 1,108
From: Michigan
RE: 6 to 8 swap
You will destroy the original rear with a v8, it are not rated for the kind of torque a v8 put out. If you hope not to destroy it with an v8 you would have to drive like a grandma. Also it depends what trans it is if it can handle it or not. If you want more info than you could ever use for the swap head over to the FAQ section, it will also answer most any other question you have. And welcome to the forum.
6th Gear Member
Joined: Oct 2006
Posts: 8,162
From:
3rd Gear Member
Joined: Jun 2006
Posts: 528
From: Northern Virginia
RE: 6 to 8 swap
Contrary to popular belief, the 7.5" rear will not instantly disintegrate upon mating with a V8.
Has anyone here honestlydestroyed one? (I ask this question seriously, because I have not been able to break mine - even trying.) Now, I chalk my experience up to a number of factors:
[1] I have an automatic transmission (C-4) and 2.79 gears.
[2] I do not have racing slicks, or any locking differentials (obviously with the 7.5"). A single wheel spins.
So I think there's enough "give" along the drivetrain not to destroy it. Your mileage may vary, but I'm running a fresh rebuilt 302 with a mild cam, performer intake, and performer 600 carb. If you believe the paperwork, that combo is worth almost 300 ft lbs of torque (at the flywheel).
Should you change your rear to an 8 or 9"? Yes. Do you need to keep the car on stands until you get one? I wouldn't.
Good luck with your decision.
Has anyone here honestlydestroyed one? (I ask this question seriously, because I have not been able to break mine - even trying.) Now, I chalk my experience up to a number of factors:
[1] I have an automatic transmission (C-4) and 2.79 gears.
[2] I do not have racing slicks, or any locking differentials (obviously with the 7.5"). A single wheel spins.
So I think there's enough "give" along the drivetrain not to destroy it. Your mileage may vary, but I'm running a fresh rebuilt 302 with a mild cam, performer intake, and performer 600 carb. If you believe the paperwork, that combo is worth almost 300 ft lbs of torque (at the flywheel).
Should you change your rear to an 8 or 9"? Yes. Do you need to keep the car on stands until you get one? I wouldn't.
Good luck with your decision.
3rd Gear Member
Joined: Apr 2004
Posts: 686
From:
RE: 6 to 8 swap
ORIGINAL: khoustonm
hey guys i'm new to the forum and i'm looking for some advice. i drive a 1970 250 ci straight 6 mustang and thinking about upgrading to an 8. will the original rear end on this car handle a mild V8? what about the transmission?
hey guys i'm new to the forum and i'm looking for some advice. i drive a 1970 250 ci straight 6 mustang and thinking about upgrading to an 8. will the original rear end on this car handle a mild V8? what about the transmission?
4th Gear Member
Joined: Aug 2007
Posts: 1,692
From: Houston, Texas
RE: 6 to 8 swap
ORIGINAL: crunchyskippy
Contrary to popular belief, the 7.5" rear will not instantly disintegrate upon mating with a V8.
Has anyone here honestlydestroyed one? (I ask this question seriously, because I have not been able to break mine - even trying.) Now, I chalk my experience up to a number of factors:
[1] I have an automatic transmission (C-4) and 2.79 gears.
[2] I do not have racing slicks, or any locking differentials (obviously with the 7.5"). A single wheel spins.
So I think there's enough "give" along the drivetrain not to destroy it. Your mileage may vary, but I'm running a fresh rebuilt 302 with a mild cam, performer intake, and performer 600 carb. If you believe the paperwork, that combo is worth almost 300 ft lbs of torque (at the flywheel).
Should you change your rear to an 8 or 9"? Yes. Do you need to keep the car on stands until you get one? I wouldn't.
Good luck with your decision.
Contrary to popular belief, the 7.5" rear will not instantly disintegrate upon mating with a V8.
Has anyone here honestlydestroyed one? (I ask this question seriously, because I have not been able to break mine - even trying.) Now, I chalk my experience up to a number of factors:
[1] I have an automatic transmission (C-4) and 2.79 gears.
[2] I do not have racing slicks, or any locking differentials (obviously with the 7.5"). A single wheel spins.
So I think there's enough "give" along the drivetrain not to destroy it. Your mileage may vary, but I'm running a fresh rebuilt 302 with a mild cam, performer intake, and performer 600 carb. If you believe the paperwork, that combo is worth almost 300 ft lbs of torque (at the flywheel).
Should you change your rear to an 8 or 9"? Yes. Do you need to keep the car on stands until you get one? I wouldn't.
Good luck with your decision.
While both would be nice, take all the advice you get with a grain of salt!