How much HP can these frames Handel?
 

Hi!

Picked up a 1992 Classic Roadster rear end is lose with the stock Mustang 2 suspension. Plan on upgrading with data available on this site. It has a three speed automatic that shifts really well. It has a 302 from the 90’s and I’m looking to either upgrade to a 351 or cross ram with old school supercharges. The question is could this project work on this set up?

Thanks for your educated respond!

More than you think and less than you have.

I thought you were going to make a play on Handel's Water Music.:LOL:

Well, well, the sleeping giant awakes. :)

The CR chassis is very stiff and will handle more than you’ll apply to it. The rear suspension is fox body with custom length lower control arms, not mustang 2. People have gone very far with just adjustable uppers and boxed lowers. I’m near 600hp with others making more. The chassis is not the limiter.

On a factory tour July 31 1991 I was told 1000 hp. I also saw phone bank room with 50 people answering phones.
Jeffery Davis (president of CMC in 1978 and LLC owner of all the Florida companies to follow) was president and LLC owner of Classic after coming aboard in the Heritage deal where he was Vice President.
He bankrupted Classic but with Classic guys and his Cobra knowledge he built his best car.
The Excaliburs are same chassis’s with 1 piece main rails and rear extensions.
If you can bend a chassis call NHRA or NASCAR they are looking for engine builders with skills.
Jeff lives in a mansion in Florida and runs a cosmetic surgery center with payment plans.

In their statement of power handling capability, did they ever share how they came to their 1000HP representation? Was there some sort of testing which they performed to determine that number, or was there design criteria that were used in fabrication to help sustain that performance, how did they come up with their number?

Usually when you are talking about chassis power handling capabilities the metric that is frequently used is torque not horsepower. The thing you would have a high interest in when building one of these vehicles is the chassis torsional rigidity which is not measured in horsepower.

If I have an engine that makes 1000 hp at 1600 rpm or I have an engiine that makes 1000 hp at 10,000 rpm, I have engines that place very different loadings on a chassis. 1000HP @ 1600 rpm produces a little north of 3200 ft/lbs of torque. 1000HP @ 10,000 rpm produces a little north of 500 ft/lbs of torque. Both engines produce 1000 HP. Which engine do you think would beat up the chassis more?

Horsepower is a ruse when used to evaluate the torsional ridgity of a chassis. The force you need to pay attention to is torque — and I would be willing to bet that the flamboyant 1000 HP representation for what that chassis could handle was nothing more than a pretty unscientific wild ass guess. Most importantly, without any testing what so ever to support the representation.

The guy was a car salesman, the reference to the phone scam operation…
Ads in Kit Car, Hot Rod, Car Craft, raking in the cash
Ya know Duchess Capital (Sugar Sand, Gekko boats and Classic Roadsters) formed in 96 and the 2 guys turned it into a multi billion dollar capital management company. One was bared from trading by the SEC recently finally.
Duchess MG-TD is a Chevette powered Classic Roadsters car.
“Classic Elegance… Rain or Shine”
The most successful kit car company ever.
Google it up

I have a torky 390FE stroked to 445CI in my CR. Never felt like the chassis was unable to handle it. Suspension and drive train are pretty stout. Est.520HP and 540TQ. I cant imagine the need for more. No matter how fast you build it there will be somebody else a lot faster. What was the output of the Bill Cosby Cobra??

John

Even Cosby turned down the Super Snake!

Thanks everyone!

So the 92 CR has a fox body rear ended? I know it’s an 8.8, so when I start rebuilding should I be purchasing 90 Fox Body rear end parts?

Thanks again for your insight!

I have a 9 inch in my CR. The suspension is Fox Body but the rear axle doesn't need to be. I bought the 9 inch already shortened, with the proper 4 bar mounts welded on, a posi diff and converted to disc brakes from Currie Enterprises back when I put my CR together. There are probably better sources for such a package these days but you should be able to source a pre-made unit.

If you are thinking big HP/torque, the 9 inch is a proven answer. I did also add on a Panhard bar to the setup and the car handles like it's on rails :D

While the 9" Ford centers are unquestionably stronger in their built condition than the best 8.8" rear ends, the operative words are in their built condition.

The pinion stems on the 9" Fords do not exceed, let alone equal, the pinion stem strength on the 8.8" Fords until you get to the ProGear pinions that require a new carrier. Additionally while a 9" ring gear is unquestionably stronger than an 8.8 inch ring gear, the strength improvement is marginal at best.

More food for thought ...

The pinion on the 9" gear set is substantially lower than the piniion on the 8.8" gear set. This puts an additional angular displacement on the drive shaft to accomodate the lower pinion and modestly complicates the alignment of all the pieces.

More to consider, we have 2,100 to 2,500 lb cars. Ford uses the 8.8 rear end in all the performance Mustangs and it survives very well as these cars run low eight and high seven second elapsed times at 180 moh in the NHRA Showroom Stock class, behind supercharged engines producing in the 750 to 800 hp area and frequently higher. We are not even close to that level of abuse.

Lastly, if you want to make improvements in the way your car handles varying road conditions and turns, an IRS makes a big difference over a straigt axle or as some call them stick axles. Ford sells over the counter complete 8.8" IRS center sections with a posi carrier for around $1,200 list and after Tasca gets done discounting them you might come in at or below $1K — and it's all brand new CobraJet HD stuff!

Here's a link to it on the FRPP site;

click here => 2018 - 2022 Mustang Loaded Diff Hsg

BTW did you notice they do free shipping?? It is also available in either cast iron or cast aluminum. Lots of inducements to use these new parts.

Granted you still need to mount it in the chassis and buy hubs and axles from FRPP but the package is pretty impressive and nicely thought out — it's also seven second, 180 mph strong in a 3500 lb car! Unless you were planning on going way quicker and faster it's a walk in the park in a Cobra replica.


p.s. Here it is with the $!K price point at Summit Racing, click here => Ford Super 8.8

I'm all in for either the Ford or Jag IRS.

8.8 IRS in NHRA? WTF?
The 2019 Mustang Cobra Jets have Strange Engineering 9” aluminum center section 4 link straight rear axels . Bare body’s are sent to Watson Racing for rear end and cage, shipped back to Ford for paint then back to Watson for assembly.
9” carriers only take a minute to change.
Panhard setup is sweet I’m telling my friends I made it up.

You sure it's an 8.8 rear end? When I went to Classic Motor Carriages as I think they were called, the one on display on the paved slope out front had a 7.5 Fox body rear along with a 305 Chevy and Turbo 350. I recall the shoddy door handles and hood hardware that were just screwed into the fiberglass and almost came off in my hand. Pretty much decided "No thanks" right then and ventured back out to what seemed to be the worst 'hood in Miami.
I would still get calls from them every few months for another couple years.

http://www.clubcobra.com/photopost/d...CB1B48C00.jpeg http://www.clubcobra.com/photopost/d...5E226FAEF.jpeg Classic Roadsters was in Fargo, CR II in Minnesota.
CMC in Miami.
Two different companies different cars.
Here’s an 8.8 with GT Quad Shocks in a Classic Roadsters.
Good for small block, for big block use 9”.
The front arm bracket is bulletproof, making more in 304 stainless.

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.

I had a CR (Series 1 1992 build, may have been one of the last 3?) that was brought as a roller in 92, I brought it 2016, 60% complete when I got it. It had a 65-date coded 427S/O with TKO-600 5-speed, and SVO 8.8 Rear end, with harden 'Strange' ? axles. 526HP @ flywheel, a friend that owns 'Old School Garage' in Port Orchard Wa. got the car up & running, (he was the crew chief for Bruce Leven on his 934/935 Porsches in the day) He told me don't worry about frame it will handle what you have, leave the limiting factor your tires (Cheaper to replace) which I did with M/T ST's 275-60-15 rears. Body & Frame on CR are IMPO top notch.

Yeah, but just think how much quicker your Cobra would be with your wallet that much lighter. :LOL::LOL: