Is a 7.5 10-bolt better than an 8.2?

Rich67 · Jul 21, 2004

In the May 04 issue of Chevy Hipref. mag. there is an article entitled "7.5 is enough". It's an article about building a 7.5 10-bolt to handle 400hp at the (rear wheels)!! They list the parts total as $965.00

Now the same magazine has another article on their web site,http://www.chevyhiperformance.com/howto/68238/ This article is about the 8.2 10-bolt. They give it no consideration at all. They say the 8.2 is very weak and to swap in an 8.5

So my question is, what is it about the 8.2 that makes it so weak. I thought it was the smaller ring gear diameter but apparently that is not the reason because the 7.5 is smaller yet. If a 7.5 can handle it why can't an 8.2?

The reason I'm asking is because I have an 8.2 in my 67. MY future plans are for a 383 in the low 400hp range. Can the 8.2 be built to handle it?
Thanks,
Rich

dawg · Jul 21, 2004

the outer housing on an 8.2 rear is weaker.
but there is kits to strenghten it.

a67 · Jul 21, 2004

IIRC another problem with the Chevy 8.2 is that the pinion gear shaft is small in diameter. They have been known to shear off.

The Pontiac (Firebird) 8.2's are stronger. The pinion gear shaft and yoke are larger, axles are retained by the axle bearing and retainer plates (no C-clips), and some came with a 4-pinion posi setup (4 spider gears).

Bob.

MarkM · Jul 21, 2004

Originally posted by dawg:
the outer housing on an 8.2 rear is weaker.
but there is kits to strenghten it.

Weaker then the 8.2"?

big gear head · Jul 21, 2004

I don't think the 8.2 is weaker than the 7.5. They both have a 1.438 diameter pinion shaft. The 8.2 has 3 inch axle tubes and the 7.5 has something like 2 1/2 inch tubes. The 8.2 has 28 spline axles and the 7.5 has 26 spline axles up to '90, and 28 spline axles after that. The 8.2 has a much larger ring gear than the 7.5. When you add it up the 8.2 comes out equal or on top in every case. The 8.5 is better than both, but still has weak points unless it is updated to strengthen these areas.

J early · Jul 22, 2004

For 965 bucks why would't you just build a 9", 8.8" or chevy 8.5"

pdq67 · Jul 23, 2004

I would ask myself that too!!!

pdq67

Eric68 · Jul 23, 2004

I can understand why he is asking - especially if you read that article. It seemed to me to be one of those articles that catered to the masses of 3rd gen owners out there (and the vendors making parts) rather than stating the simple truth that 7.5" rear ends are weak . . .

Is a 7.5 10-bolt better than an 8.2?

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