Although I never checked myself, I read somewhere recently that the 9" when compared to the 8" is roughly 90 pounds heavier.

Either way, this is not a good area to shed weight. Keep the 9".

Getting the car under 2500 pounds is easier than you think.

Remove:

radio/speakers
back seat
front passenger seat
heater box/controls/blower motor

Convert to:

a 4 link rear suspension (removing the leaf springs)
Aluminum heads
Aluminum block
Aluminum radiator
Aluminum intake
Aluminum wheels
FG hood
FG aprons
FG fenders

It all depends on what your goals are and how much money you want to spend, but swapping a 9" for an 8" usually isn't one of the considerations.

Dave

 

If you never drag race, never launch hard coming off a stop light, never bang gears to hear the "chirp", and never run any tire that's grippier than a street-only summer performance tire, you can probably get it to live a fairly long life. One of my other cars is an EFI 355 with350-ish to maybe 375 HP & torque(flywheel) driving through a Tremec 3550 and a GM 7.5/7.625 axle. The diff and gears have held up just fine, but the preload in the Auburn Pro posi has not fared nearly as well.

But I suspect that those are some mighty big "ifs" for most folks here, especially those with 400 HP or better. Keep the 9, or maybe consider an 8.8 if anybody builds one to fit.


Norm

 

Actually, the weak point in the 8" is the two-pinion differential, not the axles.

If you drive casually, I doubt you'd destroy a four-pinion 8". But I bet some hard launches would bring it right to it's limit. I wouldn't put an 8" behind that torquey of a motor. If you're hell bent on saving weight (yes, the 9" is much heavier than an 8"), go to an 8.8" rear. Lighter, but still stronger than an 8". I still don't think it's worth the time, money, and effort unless you're track racing it, but it's your car

 

Yeah, I wasn't saying trade for an 8. By all means, keep the 9 inch. I am changing my carrier out, and putting in a Detroit True-Trac, so I will therefore be making the rear stronger. I think with this mod, I won't have any problems.