unibody twist

[Cudafever]

How much power will a 70 ply Barracuda take before it cause problem with the unibody(sp)

Building a 408 stroker for it now, and worry that it may be two much for the ol body.
If I don't run out of money it will be a 11.75esh compressioned, forged assembly, .600 lift hyd roller with RHS 2.02 heads LD340 maniflold with 750 Demon.

This is a full body car aka 3760 pounds with me in it.

My car at pressent: .474 cammed 340 w super comp headers. built 727 with manual revers valve body, 2800 stall and 4.56 gears in my 8 3/4 rear.
Super Stock springs in the rear with pinnion snubber. MP race shock on back(non adj) and worn out old shocks up front.

I do have frame connector for it, but have never installed them.

Do i need to de tune the stroker so a roll cage is not required, or will the frame ties be enough.

Have no intention of using a trans brake. or N.O.S
Will allway be foot braked. but run as hard as i can with a foot launch.

 

[Juan Veldez]

Besides the stall speed, the last two of your sentences are what counts, right behind "Are you running slicks"? The twisting comes almost entirely from the launch. Just as with all metal parts, they eventually wear out, but gut level says your fine without the connectors for many passes at the strip as long as your floor is not showing any signs of fatigue or rust currently. The frame connectors wouldn't hurt and may give you more consistent 60' times. Cage requirement will be based on sanctioning body ET limitation and I don't think you'll be running that quick for that requirement to kick in. My comments are for any car, your best bet is fine someone running quicker than you in a similar body and pick their brain. Good luck, keep the shiny side up.

FYI: I went 9's/123mph in a car and 7's/175mph on a bike in the quarter.

 

[Cudafever]

Yes, running 26 tall/10 wide/15 slicks. Have a fresh set that will go on with the new motor.

The ol girl has rusting rear panals but the trunk pan is complete and solid.

 

[burntorange70]

Put them frame connectors on and you should be good to go.

 

[Juan Veldez]

Then I agree with "burnt", if you have them, put them on. Better safe than sorry, especially when running slicks.

 

[pisser]

Be sure to weld your subframe connectors to the subframes instead of bolting them in. and weld any places where the connectors touch the floorpans to each other. but be careful to not burn thru to the carpet. pull carpet away while welding.

 

[Cudafever]

Looked at the IHRA rule book last night. A role bar isn't req until 11.5
And a role cage was way faster then that.

High 12 Low, Low 13 would make me happy Thats a long ways a way from 11.5(11.49)

 

[upnover]

us car tool makes some really nice ones, they make the car look like a factory framed(non unibody) car.

 

[Cudafever]

I ended up going to a frame shop and had some frame conectors installed on there frame table. Best money spent! no twist of the frame, and traction hasn't been a problem, with my new 408. Maybe next year when i replace my pos 3000 stall for much better built, 4500 stall converter.

 

[HPP]

How much power will a 70 ply Barracuda take before it cause problem with the unibody(sp)

IMO, about 75 horsepower. After 40 years, these cars need all the help they can get. Glad you have em in now.

 

[moper]

Yeah - any engine with a little extra power will twist the car. It snaps back for a while... Then it doesn't...lol. I put them on everything that has a V8.

 

[Cudafever]

Yeah - any engine with a little extra power will twist the car. It snaps back for a while... Then it doesn't...lol. I put them on everything that has a V8.

Yeah the first thing i notes was the front end coming up even when i launched the car. but what shocked me was when i put it back up on jack stand, just how much it didn't flex.

Jack up front end by K member, install jack stands, jack rear end up and install jack stands under axle. Now to get the front end up high enough jacked up each side separate. what happened this time was that the rear axle came off the jack stand. seamed a little scary have all the cars weight on two jack stand.


It never did that before and i didn't give it a second thought then as it was the leaf spring taking up the twist.

well i guess not it was the unibody flexing :tongue9:

 

[moper]

If you don't think you need frame connectors, put a jack under the driver's control arm and jack the tire 1" off the ground. Then open the driver's door. Jack the car up another 3" and try to close it. If it closes it would shock me.

 

[mmissile]

I'd also add the connectors. My buddies 11-second, small block, 4-speed T/A was cracking the cowl, back in the 70's.