Car climbs then falls 1.58 60 foot

[PONTIACMAN3]

Please help me out here I have a 78 lemans, 575 horse the car hooks hard off the line then seems to fall hard, then pull again, moroso springs up front and shocks set at 90/10 rear has lift bars and solid lakewood uppers, believe the bad combo maybe that the cars has belltech springs in the rear, says they make the car sit 1.5 inches lower than stock, are these springs to soft or stiff or is the front coming up to quick, also i run an air bag in the right rear at 17pounds.... this air bag fills the whole spring because it is a small lowering spring, could it be keeping the rear too stiff seems like limited travel with bag in, 1.58 60 foot 11.0 @122 car should do 10's and I feel this is what is holding it back, please advise p.s. 5500 converter and have left everywhere from 3000 to 5500 off trans brake 1.66 to 1.58 60 foot still gets alot of air then slams down and regains momentum, thanks for any info!!!!!

 

[CutlassRacer]

Silly question, but do you have jet extensions for the rear jets? Have a friend watch the car and have him tell you if it is spinning, or putting out any smoke (have him note the color also).

 

[PONTIACMAN3]

jet extensions are in motor is brand new,no smoke wheel does spins one rotation then the car drops , it does not want to carry through! thanks

 

[slimbo]

you can actually see in the picture that right rear tire is about to unload. does the car have a arb or a stiff sway bar?

 

[PONTIACMAN3]

no sway bar, thanks for the input you guys i need all the help i can get.......was going to order moroso springs for the rear so i have normal springs .....to start i really think the small lowering rear springs were too small and stiff along with too much extension in the front control arms, and the front shocks being set at 90/10???????

 

[BadLatitude]

Go to http://www.baselinesuspensions.com and read the articles on hooking , setting up and getting your geometry. Its way easier to lin you to there then type for 20 min.

To me it sounds like your car is unloading. Id ditch the lowering springs. the stock rears are better. coil overs are best and you can really dial the car in.

 

[PONTIACMAN3]

thanks you guys have been a great help!!!!!!! great website!!!!!!!!!!!!!! please if anyone else has reccomendation go right ahead I am by far no professional, i just know how to stuff a good engine in a light car with alot of gear and converter 11.0 is fun but I know it can go deep into the 10'ssssssss thanks again!!!!!!!!

 

[Time Warp]

I may be off base here but what lower arms are in the car ? I was under the impression you want the lower control arms at or near parallel with the ground .

 

[juicedimpss]

any video of the car?

 

[slimbo]

from the pic you can see it. the rear is stiff but still twisting and unloading. stock rear springs and a good arb or a spohn sway bar. my 3800 pounder will go 1.50 60 foot all day on radials.