How much HP can these frames Handel?

[eschaider]

Sunman is right. The Factory Showroom Stock cars do use a 9" Ford, not an 8.8" Ford. My bad, and my apologies to those I unintentionally misled.

That said, we have used an 8.8 inch in a 3500lb 03/04 Cobra that was changed from the original 3.55 R&P to a 3.70 R&P about 15 years ago. That same 3.70 R&P is still in the car today and runs 8.4x ETs at 160+mph.

The 8.8 is an excellent choice for our Cobra replicas. It is easily more than strong enough, relatively compact, and comes in an IRS implementation which is more desirable for our kind of application than drag race applications.

Although it sounds like a broken record, the 9" Ford in built form is decidedly stronger than the 8.8 in similarily built form. But, and this is an important distinction, the strength is not necessary for our application. As strong as the built 9" design is, the 9.5", 10.5", and 12" ring and pinions are even stronger, but we would not consider them.

If you ignore the higher price and look at the rear end, the real issue is adequacy. While the bigger R&P choices are unquestionably more substantial, their strength is not required. The strength of the 8.8 is way more than adequate and substantially more than the Dana 44 that the originals used.

If we ignore the price premiums for the larger R&P solutions, the adequacy argument still points us at the 8.8 solutions.

Decades ago, I was in the market for a speaker upgrade for my stereo. The speakers I had my heart set on were a pair of Ohm-F's that ran about $3,500 at that time. The sales rep at the stereo shop put me through a blindfold test in the listening room, and the best-sounding speaker pair turned out to be $2,500 cheaper! If I had not done the listening ‘adequacy test,' my wallet would have been an additional 2,500 dollars lighter.

In the FWIW bucket, instrumentation repeatedly would show the Ohm-F speakers to produce a substantially higher fidelity rendering of audio frequencies /tones in the upper-frequency ranges. My ears could not distinguish the difference because I could not hear those frequencies.

The adequacy test the sales representative taught me that day has stuck through the years and served me well. Nine-inch Ford rear ends are indeed carriers of both beauty and strength. In our application, they are overkill. The Dana 44's will serve us very well, and the 8.8 Ford IRS centers are all but indestructible — and a lot more cost-effective.

Ultimately, what each of us chooses for our rides boils down to personal preferences and cost. If your personal preferences dictate a 9" Ford solution, by all means, you should do that. It is, after all, your car, your money, and by definition, your choice.

If you are willing to embrace the adequacy logic, you will find many miles of smiles and excellent service from an 8.8 IRS solution in your ride.