View Full Version : 55 coupe with a chevy squats hard on launch

02-19-2010, 10:20 PM
I have a 55 coupe with a solid lifter 327 and a 4 speed. as we are slowly working out the bugs in the car,we get to drive her a little more. When i get on her, she squats hard in the right rear, rubbing the tire. What have you guys with similar setups done, or can anything be done to help alleviate this. the frame and suspension is all stock, with new shocks and rear bushings. I have trimmed the center crossmember to clear the driveshaft, and it has shackles on the back but sits level. it still has the stock tranny crossmember in place.

they just keep following me home

Dick Steinkamp
02-19-2010, 10:33 PM
Here's my '54 Starliner. Solid lifter 327, close ratio T10 4 speed, 4.27 gears in the stock Dana 44 housing with a Richmond Gear locker and flanged axles. Slapper bars and coils around the rear shocks (little to no preload). Stock front end (cut coils). Stock 2 piece drive shaft. I also left in the stock trany crossmember just to help stiffen the frame a little. Nothing is mounted to it.


Relatively small tires (215 75 15 rears). I did get quite a bit of wheel spin (even with the locker) with a hard launch. Perhaps with bigger or stickier tires it would squat...but didn't with the above combo.

Dick Steinkamp
Bellingham, WA

02-19-2010, 10:45 PM
thanks. I will give the slappers a try. Mine has the tapered shaft rear, so i have only hit it while rolling. I am running a saginaw 4 speed out of a monza

they just keep following me home

02-19-2010, 10:47 PM
quote: "I have trimmed the center crossmember to clear the driveshaft,"

Does this mean the car has a single driveshaft, but originally had a 2pce driveshaft? If this is the case, other's have reported the driveshaft tunnel needs to be made larger as a single driveshaft will hit the original sized tunnel. I swapped rearends last summer and was going to convert to a single driveshaft but other members convinced me to stay with the 2pce set up... no problems with the 2pce set up. What is the tire rubbing on? Junior.


54 Champ C5 Hamilton car. In my family since 1958.

Mike Van Veghten
02-19-2010, 10:50 PM
Dropping or squatting under launch is caused by spring wrap-up/lack of proper shock action. While you may or may not get wheel hop, the body weight is reacting from the power causing the pinion to try to climb the ring gear and causing the spring to react in such a way as the spring can no longer properly hold up the car.

For good traction, from best to worst (roughly) -

Four link
Three link
Cal-Tracks/Competion Engineering traction bars
Restack the spring to resemble the old Chrysler springs
Slapper type traction bars
Stude type traction bars

There are many variations of the above setups so not "every" type is mentioned, but the above or their varations will provide your car with proper traction and a "no squat" operation.


02-19-2010, 11:12 PM
i cut the bottom out of the centerhole to clear the driveshaft. I have had no problems with the tunnel itself, only where the driveshaft passed through the crossmember. I do have shackles on the back, from years ago, that keep the car level, which is about 2 inches higher due to the lighter chevy engine. my fear was more related to frame flex than springs., especially since I cut out the bottom of the center crossmember. And this thing moves enough to make me wonder. My previous toy for years was a 66 chevy half ton, which basically had factory ladders, and hooked up every time. Thanks for the input. I had been running the slappers through my head, as well as a loaded helper springs, and individual air shocks. My dad drives the car mostly,so she doesn't get much abuse unless i drive her.

they just keep following me home

02-20-2010, 04:30 AM
Here's your answer:


Robert (Bob) Andrews- on the IoMT (Island of Misfit Toys)
Parish, central NY 13131

02-20-2010, 06:42 AM
I am running slapper bars. They came off a Nova. They are not the clamp on to the spring pack boy racer type. They are Lakewoods. They had to be shortened since they were too long to hit on the spring eye,which is where they should hit,NOT the spring leaf behind the eye.
These type slappers take the place of the flat locating plate the u-bolts go thru.I measured,split the factory plate and welded it to the bottom of the traction bar plate,then redrilled the holes to the factory plate. This also gave me the factory lower shock mount.
There is a U bolt on the front that goes around the spring pack.This is a anti dive loop to keep the traction bar from rotating toward the ground on heavy emergency braking.
I also used urethane snubbers bought thru Summit,trimmed for 1/4 inch gap. Keep the gap equal side to side so they will hit equally. My Lark lifts upon acceleration and upon shifts. Be easy with the Saginaw,I hurt one behind a 200 horse 305 in my old ElCamino.

02-21-2010, 06:55 PM
the beauty of running the saginaw is the price- I have 5 of them with a net investmant of about 150 bucks. so if i blow one up, i'm good. cheaper than replacin a muncie at least. The one in the car right now cost me 80 bucks at pick n pull. I also have one in my 59 el camino behind a 427. I expect to hurt that one at some point, although so far i have just disintegrated my spider gears. i buy rearends as i find them now too.

they just keep following me home

02-21-2010, 07:20 PM
quote:I do have shackles on the back,FWIW, I don't consider longer/reversed spring shackles as good science. If it were my car, I'd install 6-cyl springs in the front and heavy duty leaf springs in the rear with OEM shackles. Just getting the car down where it was designed to be will help, plus the heavy duty rear springs don't wrap up as much.

The po'boy/shadetree rear spring method is to find a spring same width and cut the eyes off the main leaf and insert it under the existing main leaf.

thnx, jack vines


02-21-2010, 09:34 PM
the most effective way to get anti-squat into a car is to raise the front spring eye. I have no idea if this is possible or practical on your car. Lowering the back of the spring will have some effect but to a lesser extent. the third option and least effective is to stiffen the spring or use some kind of traction bar. Neither of these solve the geometry problem, only resist the force. You can and probably should add a half leaf to the front of the spring or even two. Making the front of the spring very stiff resists the twisting without having much impact on ride. If I could figure out how to do drawings on a post I'd draw the geometry but Herb Adams has an excellent book on suspension geometry that will give you lots of insight.