[steve25]

That’s why I posted it !
In a friends F body WITH a driveshaft loop he had the thing still fail and bust thru the floor only 1 inch away from his seatbelt hold down on the side of the tunnel,

Had he not had the loop it would have grabbed That seat belt , pulled it tight and just cut him right in half!

[4zpeed]

Originally Posted by lust4speed

Seems like I've seen more frame flex than cracking. This photo is of a friend's '67 quarter panel. He had the factory 4-speed frame stiffeners in place since new but over time the bolts had loosened which allowed the bolt holes to hog out and effectively negate any ability to stiffen things up.

Anything over about 1-1/2" lift in the rear will get you into wheel hop. Best to stay close to stock control arm angles.

I was just about to ask if your friend has a You Tube channel.

Take a look at this video, this guy actually replaced the original

body mount bushings with poly's and the problem got worse.

https://www.youtube.com/watch?v=-NdFIAt7ysE



Frank

[mchell]

Originally Posted by


I was just about to ask if your friend has a You Tube channel.

Take a look at this video, this guy actually replaced the original

body mount bushings with poly's and the problem got worse.

[url

https://www.youtube.com/watch?v=-NdFIAt7ysE[/url]



Frank

Interesting !

[lust4speed]

Think the take-away is you can't ask the body to do the work the frame should be doing. Until frame flex is eliminated it will be transferring the flex to the body and the stiffer mounts simply asked the body to do more of the work. Leaving softer mounts in place doesn't do anything for the launch, but it does prevent additional flex transfer.

Solution has to be in stiffening up the frame. I went back and retightened my brace bolts on the street car and called it good because it no longer sees track time. My friend with the quarter problem purchased some very nice tubular braces that look like they will be much stiffer than the stock angle pieces. Unfortunately in his case it is like the old adage of closing the barn door after the horse gets out.

[STEELCITYFIREBIRD]

Originally Posted by DaleO

After setting up a limited slip axle and adding slicks what is the next smartest thing a guy can do?

Add a driveshaft loop?��
And see what breaks next! ��

[OCMDGTO]

X10 on the driveshaft loop so you're legal at the track and check u joints. Make a couple passes and get a baseline.. If your rear is an 8.2 start planning on a replacement. High 12s doesn't require major mods

[Chief of the 60's]

Originally Posted by STEELCITYFIREBIRD

Add a driveshaft loop?��
And see what breaks next! ��

Rear axle shafts and engine mounts.

[Formulajones]

At your power level you really won't need much. 13.50's at 103 is a great start, and tells you the car is already capable of high 12's as is. I've gone mid 12's with completely stock 50 year old issue suspension without anything more than a sticky tire. I eventually pushed that car to 11.70's with more engine, with a not so great 60 foot, and all I had done at that point was unhook the front sway bar. The car would eventually go 11.40's with no hop bars, adjustable shocks. Very basic setup for very little money. Basically the same setup my father is going 10's with and cutting 1.4 60 foot times.

If you don't plan more power upgrades, and since you already have some sticky tires, I'd make a trip back to the track with the new tires and have some fun with it. See where you're at, how the car does, and then make some decisions before spending money on other things you may not need at all.

My bird is going nearly 13 flat (high 12's corrected) and everything on that car is 50 years old. There are no aftermarket parts in the suspension anywhere. Just modified the front control arm bushings and sway bar bushings to allow a little more front end movement, it has oil filled shocks, the rear suspension is untouched with stock replacement 50/50 gas shocks. All the springs are original issue. I've spent literally no money on the suspension, lol. At that power level it just flat out works, and still daily drives like a stock car should.

Best of luck, most of all, have some fun!!

[XLR8STEVE]

It is a fun journey for sure going from 13s to 11s. The video camera on slow mo is your best friend. Make a change, go test and video.

The people on these forums then can give you great advice. I got tons from these awesome people. I ended up 11.71@118 and reliable as hell. Started with a totally stock 70. Did Drag Week 2019 zero failures.

[68lemans462]

i'd go for a driveshaft loop next!

[ta man]

Good sticky tires, good or upgraded u joints and a driveshaft loop and go from there.
I'm into the 10's and my biggest traction aid is sticky tires. Stock suspension second gen Firebird with just cheap 3 way front and rear shocks.

[TCSGTO]

Originally Posted by ta man

Good sticky tires, good or upgraded u joints and a driveshaft loop and go from there.
I'm into the 10's and my biggest traction aid is sticky tires. Stock suspension second gen Firebird with just cheap 3 way front and rear shocks.

I agree, good tires on a stock suspension in decent condition is all you need well into the 12’s and beyond.
If you’re going to do some serious bracket racing there are some things you could add that may help consistency but you won’t go any quicker.

[DaleO]

Thanks everyone for laying out a sensible and cost efficient plan. I have a grocery getter compared to all of yours and thanks for your time.

[Baron Von Zeppelin]

Originally Posted by DaleO

1967 GTO, 3.23, 428, TH400 with Cliff influenced 9.5 inch convertor.

1 or 2 fifty pound sand bags behind the back seat - in trunk.

[Vid]

For under $700, UMI makes a pretty attractive rear kit.


Sent from my iPhone using Tapatalk

[ZeGermanHam]

^^^If you're going to go through the trouble of replacing/updating the rear control arms with UMI products, I'd recommend opting for their Roto-Joint spherical bushings rather than the standard polyurethane.

[ta man]

Originally Posted by Baron Von Zeppelin

1 or 2 fifty pound sand bags behind the back seat - in trunk.

A few years back. I had about 150 lbs of softener salt in my trunk to aid traction on a cool night. When the car hooked after the first pass and we realized the track wasn't that bad..we quickly pulled the bags out and picked up another tenth and a mph real quick. Weight helps if you want to tune your 60ft as far as carb or timing if you are traction limited.

[2+2=421]

Look at what gears you have? Definitely want a stall converter depending on cam and gears,minimum stall converter at 2800, drag radials, stiff poly bushings, practice your launch..start there..

[HWYSTR455]

You can double-duty a street/strip car with good adjustable shocks, but not cheap.

Yes on the roto joints or the GW ones.

Body bushings are a touchy subject for many, but to throw it out there, solids are the way to go. People that say they increase road 'harshness' I doubt have ever really tried them, because it's just a farce.

.

[DiamondJim]

No hop bars. Adjustable upper control arms so you can set pinion angle. Large rear sway bar. 90/10 shocks in front with 50/50 rear. Air bags in coils to preload to counteract torque twist. Frame stiffeners. My 66 GTO used to twist terribly. These changes made the launch even, both front tires about 2” up. See pic.