SteveG75

Thinking about replacing/upgrading my suspensions and decided to go to the forum for advice (I know, it must be the alcohol) .

Original:
'75 Convertible - FE7 suspension, rebuilt approx 10 years/50k miles ago with the exception of T/A bushings.

Currently:
255/60R15 tires
460# front springs cut 1/2 coil for height
340# TRW rear spring
KYB GR-2 shocks
Smart Struts
Stock FE-7 sway bars front and rear
Original T/A bushings
VBP alignment specs

Lighter than stock with aluminum heads, intake, waterpump, radiator, electric fans, Hooker sidepipes, '80 seats, no spare tire or carrier.

Car handles pretty well on smooth roads but is a rough ride on anything with frost heaves, etc. Tends to steer with the rear end as you get on/off the throttle in turns. Steering is still stock but fairly responsive.
I want the car to handle but be comfortable. Possible lower the ride height as well. Future plans include 17" rims and tires when finances allow and probably a bigger (406 cube) motor along the lines of Motorhead's.

Couple of thoughts/ideas:
1) Whole VBP kit with dual mount monoleafs front rear.
2) Keep current springs but replace all bushings with poly.
3) Better shocks
4) Bigger sway bars
5) Been thinking about offset trailing arms for eventual bigger tires. May replace the TRW spring with a shortened VBP 330# unit.
6) Semicoilovers
7) New front control arms with offset shafts.
8) Corvette Steering Jeep box or Steeroids (leaning to the Jeep box)
9) Thinking about adding Hydroboost as well.

Any and all help/insight on a good/comfortable street suspension appreciated.

SteveG75

OK - 28 views no replies. TTT to see if I can get a response.

Yellow73SB

Stiff springs aren't always the answer for good handling. Ask norval he will explain it to you. he said he likes softer suspension with big sway bars.

I like really stiff springs becuase others wise it doesn't feel like a sports car.

I think your going in the right direction for your build. Your definately going the cheaper way with the semicoil overs and steeroids.

Although my advice isn't the greatest since I only have 1.5 years experience lol.

big_G

A lot of your plans, especially the low profile tires, will add to the harshness of the ride on rough roads. I would stay with rubber bushings. Now, if you don't mind the fillings popping out of your teeth....go for it!...

BigBlockk

Well, the way Herb Adams did it back in the '70's and '80's was the lightest springs that would hold everything up and the biggest sway bars you can fit on the car. That would be a 1.25" front bar and whatever will make for neutral handling on the rear. Probably something like 7/8". Then you tune with shocks, wheel alignment and tire pressure. Also a good rule of thumb is to have wheels at least one inch wider than the contact patch of the tire. This helps side wall stiffness. Take a look at the tires on racing go-carts.

To a certain extent the 'Vette is going to steer with the rear wheels no matter what you do short of completely redesigning the rear suspension. The trailing arm rear layout has a bad jacking problem. When you go into a turn hot the rear wants to raise up. This causes toe steer (bump steer) which makes the car want to swap ends at the most inopportune time. The remedy for this, believe it or not, is to jump on the throttle. When you goose it the rear suspension squats under the torque loading and the alignment doesn't change. No toe steer. Of coarse when you've overcooked it a little coming into the corner it takes some real stones to pull this off.

BigBlockk

Later.....

68427

I think you will like bigger anti-sway bars. A 1.25" is good for the front, start with your present rear bar and work up to something bigger to get the balance comfortable for you and your driving style. Those wheels look heavy, if they are you could pick up some bump compliance with a lighter wheel and tire combination. Also aluminum calipers. KYB shocks are past their prime, my experience was that they were a best buy stiff shock that didn't last long. In any case, a better shock should work and ride better than the 'ol KYBs. Also, make sure you have adequate rear toe-in, you might want to verify it yourself with some string and tape measure - the Corvette IRS toes-out under bump and extension, which can make the rear end unstable. Changing the toe back there is not easy, and few shops today seem to have the patience or skills to do it right.

Have fun

Graemeinvette

Definitely Steeroids and Hydroboost, new bushings and shocks etc. but you dont mention Smart Struts on the rear. To my mind these along with Steeroids transform the handling.

kinleydog

i put the 550# springs from vbp on my '73. i'm really happy with the ride. the ride height came down an inch without cutting the coil. i'm also a big fan of the gas-adjust shocks from kyb.

kinleydog

i also put the 1.25" sway bar on the front and 7/8" on the back during my front and rear rebuild. i'm very happy with the results.

shafrs3

1) Big sway bars
2) Soft springs
3) Premium shocks
4) rubber bushings
5) reduce unsprung weight (aluminum calipers)

You don't need offset control arm shafts unless you can't get your camber settings in spec.

SLine78

Steve,

I suggest starting with a couple upgrades that will benefit the rest of the changes you plan to make later. Begin by replacing the trailing arm bushings since their original or install new offset trailing arms in preparation of going with wider wheels and tires. Then I would replace the KYB shocks with Bilsteins. After testing with some spirited driving, you can then decide what area you feel if you changed next, would give you the most satisfaction; Springs, swaybar, wider wheels and tires changes for handling; steeroids for crisp steering or the hydroboost for some performance braking.

Mike