Lower Control Arm Re-engineer

[blackknight]

Alright, I am not sure if what I am going to say is going to help, but you never know.

I have a 78 firebird with QA1 Coil-over conversions. Factory arms, upper and lower with polygraphite bushings and polygraphite body mounts(lowered body about 1/2). I have 17" x 9.5 wheel with 275 rubber in front. It has a backspacing of 5.5 with a 1/4 spacer(to much rub on sway bar without spacer)***(if you have drop spindles i am not sure if a 17 clears your tie rod ends, mine are pretty close with this backspacing). I have factory spindles with a baer 13" track kit. the rim over hangs the top of the control arm by a 1/4"(yeah its close) and I have a small amount of tire rub at lock on the sway bar.



The front wheel is about 1/2" from the wheel well(2 inch lowered).I had 350 lb springs 11" tall.( i had to crank those springs all the way up to get the proper height)***(before i did the new wheels, had original 15 x 8 with 235 rubber) originally and polyurethane cone bump stop(about 1 1/4" tall) and I had about 1" clearance between the two. Rode well, but after i did the 17 with thin tires i noticed that they were bottoming out really bad. I have g-braces that connect my upper a arm mount to the firewall so i know when i my shock bottoms on the bump stop, the firewall creeks. I called global west and alot of people for stiffer springs, no one had stiffer then 550 for the QA1 shock design. I heard my car needed about 650 - 800lb to balance with my rear leafs. I called QA1 and they had a few old test pairs available--600lb springs(9"height i think) and 800(8 inch height), so i bought the 800. The car rides like a champ now and it fixed my problems and I have about 1.5" clearance between my bumpstop. I raised it a little bit, but still plenty adjustment in either direction). Still bottoms out when i hit a big bump, but driving on everyday roads no problem, almost never bottoms now. I have a stock 305 small block with a little upper end work(have not gotten to it yet, haha).

I figure your going to ask so, i have 180 lb leafs in the rear with a 1 racing sway bar with frame mounts and 17 x 11 with 315 rubber. I havn't had a chance to beat the crud out of it yet cauz i did the car in the late fall, but it has been good with the little fun I have had. My rear rate is alittle low but the large tire and sway bar seem to balance it out.

My car appears to sit at about the same stance and yours.