Chassis Twist

[jickyman]

Good Day to all, new member first time post.

I have a 6-71 blower on SBC and with the boost dialed back to about 3 psi, the twist is so great the car is not enjoyable to drive.
I have a chrome rear end and would prefer not to weld but will I required to correct.
I would appreciate any input, please remember I am not a mechanic.

Thanks

[Bill Cleveland]

First, welcome, jickyman! Glad to have you here.

Re: your problem, can you provide any pictures of how your chassis is set up? Or at least a description (crossmembers, or other things that would add stiffness, etc.). I know a lot of the guys run blowers (not me), and some of them should respond.

[Lee in KC]

Jickyman, are you saying your frame is twisting?

[jickyman]

Yes sir, I believe the chassis is twisting, it gets pretty squirrely quickly.
I have a dropped front axle, leaf spring, hairpin radius rods and drag link sleeve, no shocks & a corvair steering box.
Rear is a 4 bar (?) with coil over springs. The frame appears to be 2" x 4" boxed channel.
Anyone close to Baton Rouge, La?

[Bill Cleveland]

Hey, jickyman . . . any solutions yet for your chassis flex problem?

[bigdadhack]

Jickyman,
What have you tried? or found? I twist the frame everytime i'm in the throttle. My car will lift the left front tire 3" off the ground before the right front even starts to come up. (632ci BBC 800+ ft/lbs torque) Actually it's starting to put a permanent twist into the frame. We have a very similar chassis set up. 4 link rear end, no front shocks. (til recently)
I'm considering adding a rear engine mount plate. Goes between Engine and trans, mounts thru bellhousing bolts. Need to space flexplate back same thickness to make it all work. 2 thoughts on why I think this will help. 1 It will act as another crossmember closer to the front end and it will help to take some of the support load off of the bellhousing. (currently mounted at trans tail shaft and standard chevy motor mount locations) We (you included) probably have enough slot space and and slip yoke length to make it work without modifying your current trans X member mount point. and 2 it will force some of the twisting action of the motor torque to be applied further back between the frame rails. Should be trying to lift the entire left side not just the left front.
There's a good side to all of this. pulling the front end and twisting the frame like a pretzel looks cool as all hell. Built my bucket with old AA fuel Altereds in mind and those dudes twisted things hard. But all that said, they also launched fairly straight.
Is your rear end Open, Posi, spooled? Traction has a huge influence on getting squirelly at launch.
Good luck,
Hack