So says Tom. But we aren't talking about R4 autos here. And there is enough flimsiness in the differential and axles to make up for super duty u-joints. We've seen Tom's 31 spline axles sheered. Go to page 1 of this thread for a pic of one. The simple fact is the more u-joints and associated weak links you put in a driveline, the more chance you have of breakage. If you are using an auto, you probably won't break a beefed up IRS. But you also aren't putting a huge instant shock to the driveline like slipping your foot off the clutch does.

Dep

 

Heard from Chris Alston today. Seems they are NOT the same ones that are located up North of me. But they did refer me to a dealer they have in IL.


From: "JIM WRIGHT" <JWRIGHT*@cachassisworks.com>
To: "Michael L Bonomo" <mbonomo*@juno.com>
Date: Fri, 6 May 2005 07:39:11 -0700
Subject: RE: Attn Jim Wright



Hi,

We are in Sacramento CA. we are not related to the company in IL. I do
have a dealer in IL Ricks Race craft (630) 553-6183

Jim Wright
Sales Manager
Chris Alston's Chassisworks, Inc.
-----------------------------------------
I did a phone search and that place is pretty far from me. The place I thought was Chris Alston is:

http://www.alstonracing.com/

They are close and it looks like they can do the work I need to have done. At least I have a ballpark price in mind.

Dep

 

Dep do I need to remind you there r people running 1480's
w/low 9's.several and 8's. I'm with Olivier on this one I believe this system handles 1200HP safely. What more can u ask for? On the other hand if u have desire to go ***** to the Wall and do a BOB GLIDDEN 6. ET then by all means go ahead............

 

Dep, the reason why things break often has to do with excessive squatting. If you control the squatting, the IRS will hold up, even with a stick shift!
The picture of the damage to a Tom's 12 bolt axle seems to be caused by squatting. Those axles have extreme TORSIONAL strength but aren't designed to take excessive sideways force caused by squatting.
How long the IRS will last depends 90% of your suspension setup.

 

Guys...I am not talking about guys running autos. I will be running a stick with (probably) a 4.88 or higher rear axle ratio. I will be DUMPING the clutch from around 7000RPM on wrinklewall slicks. I'm not even worried about the ET. No car with that many u-joints and an IRS rear suspension is going to be able to take that kind of punishment. Why should I spend a bundle for Tom's conversion when I can pay close to the same price and NOT have to worry about that rear end letting go?
It's NOT just a problem with U-joints (people are using 1350 u-joints and even weaker ones than that and the u-joints are holding together ON NORMAL CARS) or the "Corvette squat", the whole Corvette 3rd member is a weak-link-problem waiting to happen for a stick shift car.
Have you seen the ring gears with the teeth missing on stick shift cars?
There are MANY of them posted here on the forum.
The 12-bolt conversion Tom does REMOVES metal from the ring gear to get it to fit. So are you REALLY getting a stronger setup?
I'm sure it's fine for Powerglides or Turbo 350-400 or R4 use. But there is NO rear end as heavy duty as a Ford or Dana 60 unit. Ford rears are used in NASCAR as standard equipment. The FAB 9 rear end was made
SPECIFICALLY to take a 9 inch Ford rear for drag racing. If I plan on going to a big block with even more horsepower (which is a distinct possibility), the IRS simply WON'T take the abuse.

Dep

 

If you'd go with a bigger engine it could be a problem, but I highly doubt that you'd be able to break a Tom's 12-bolt with a 302...

 

Why not go with TH400 that you have been telling us about and remove all of your fears and concerns.

 

I HAD a Turbo 400 and removed it along with the 454.
For me, performance means stick shift. I really don't care what "everyone else" is using. Autos always were and always will be for little old men and ladies who drive to church on Sunday.

Olivier: Ever wonder why the 12-bolt rear end came STANDARD on the Z-28 Camaro back in 1967-69?
A built 302 will put out power in excess of 450HP...more than many big blocks Their power is produced at the TOP of the RPM band, so keeping it up there is mandatory. The SOP for racing a Z-28 with a 302 was to mash the accelerator to the floor, pop the clutch, and then power shift through every gear. Dave Strickler's shift points on the Old Reliable Z-28 were 8200RPM. Perhaps that's why the Vette never got a 302 engine installed in it? The rear just wouldn't be able to take the abuse that a high-revving 302 could dish out.

Dep

 

Dep, the rear end doesn't care what rpm the engine revs to... It just matters how much torque it has to handle.... A 302 can produce a lot of power but has significant lower torque than a long stroke engine... Power is not the number #1 killer of rear ends...it's torque...

 

When you pop the clutch, the shock of the slicks grabbing the pavement is transmitted right to where?...the driveline...and the rear end and u-joints are the first recipients of it. If you break the tires loose little or no stress is transferred to the driveline at all. And with an auto, you don't have the instantaneous stress going to the driveline. The trans takes up a good deal of it via slippage. The weakest link is going to be the first thing to break. In the Vette...it's the IRS.
If I had a nickel for every IRS Vette I saw cough up it's u-joints and driveline at the starting line with a stick shift car, I could buy a new solid axle rear end setup for mine made out of 24k gold

Dep

 

I wonder If this guy has a Stick shift? Bad LAUNCH

 

HA!!! I love it!!! Was that Olivier's car before the paint job????

Thanks for that video

Dep

 

It's the same as running a transbrake.. I have a transbrake and will try using it soon.. I'd bet the a 6000 RPM launch with my 406 is a lot more violent than a 8000 launch with a 302... More torque = more violent...
I personally would definetely have gone with the solid axle if the cost and expected time to install would have been the same..

However, I still think that you won't break a Tom's 12-bolt setup with less than 500 HP. Stick shift or not!!

 

You can also build more motor than a stick shift can handle,Then you have to go auto or high dollar lenco which would be cool and might be my next change?

 

Big: The Lenco and Jerico transmissions are really wild. If the Jerico can stand up to a Pro Stock engine (and it can), I don't think anything I can build or install can break it

Dep

 

How fast is this car, what is the 60', 1/8 and 1/4?

Dep, how fast are you trying to go?

 

But only in terms of flight duration, and even then the Mustang only came good when it got the Spitfires Merlin engine!

 

If and when you ever have a straight axle installed, please put my “little old man” car at the top of your list for a grudge race!

http://home.earthlink.net/~geaton/

 

Greg: Not being a smartass with my answer...but AS QUICK AS I CAN GO!!!
I have no "goals" as far as ETs are concerned. It's not a bracket racer car. I will build it up, and if the 302 doesn't tickle my fancy, I'll yank it and drop a ratmotor in. But I'm pretty sure the 302 will work pretty well.
It got Dave Strickler in the low 11s with a stock engine and steel body.
I think I should be able to do at least that well and most likely better since I am not limited to a stock engine and have a lot of newer technology to pick from.

Dep

 

It's a deal!! But you'll have to drive out to me to race. Texas scares me with Dubya running around out there

Dep