Handling issue at high speeds

[Pro Stock John]

So I've got an old hacked up '67 Camaro, was tubbed probably in the 80s and got a narrowed rear end around that time.

I re purposed the car as drag and drive car.

LS 5.3
85mm turbo
T400
9" spool
3225 raceweight

I made 6 passes last weekend. Best of 6.04@123 in the 1/8th and 9.3@149.

Has a higher speed handling issue, wobbles.

Anyone running factory rear steering, factory box who has swapped on a TRZ bump steer kit?

[big gear head]

Are you running radials on the rear? How much air pressure?

[Pro Stock John]

Yeah 325 50 15 ET Street Rs, 18 psi.

[Pro Stock John]

I'm planning set up mine like my friend Aarons, check out the spacers below the tie rods:

[useless tony]

Can't comment on the TRZ kit but I will verbalize an observation of mine ... your rear coil overs look awfully close together compared to where the tires sit. Spacing them out could only benefit you and, if you don't already have one, a rear sway bar might be a nice addition.

[Pro Stock John]

Yeah those being close together probably is not helping. I'm monitoring whether I need to add an ARB, playing it by ear.

I might try to move the car back to leafs next year, will investigate my options.

[big gear head]

I don't believe that's enough air pressure in the tires. Radials need more air pressure than bias ply tires. I had radials on the back of my car and tried running 15 pounds. I had a terrible tail wag at just over 100 mph. I increased air pressure to 30 pounds according to Hoosier and it helped a lot. I changed to bias ply slicks and it went away completely.

[Pro Stock John]

Yeah if I do the bump steer / camber stuff and it's still somewhat doing this I might up the air pressure maybe even consider a stiff sidewall slick or even a radial slick.

[DW31S]

Sounds like rear tires could stand some more air to me. Easiest fix, too. I’m not sure what you mean by “wobbling”, but low slicks will absolutely make the car dance around on the big end.

[Pro Stock John]

They are drag radials but I hear you on slicks dancing around, been there in the past.

So from researching around, what's most likely happening is when the nose comes up the toe gets all messed up and the front tires up end up towing out, which is kinda of how the car feels, like it's trying turn left/right/left/right, like micro second turns if that makes sense.

I ordered the TRZ bump steer kit.