Touring Suspension

[Grizzly]

Speaking of Suspensions, my 67 is in good shape, but the rear spring is getting a little flat. Since I would like to make it as comfortable as possible for club cruises, maybe visit Nashville next summer, etc., does anyone have any suggestions for springs and shocks? It is a 300hp 327 so we are not trying to control a lot of horsepower here.

 

[WayneC]

I can't claim to be an expert, but the engineers at Chevy knew what they were doing most of the time.

The stock 9-leaf rear spring rate is around 200lbs/inch. The F41 heavy duty 7-leaf spring is about 300lbs/inch, as are the entry-level composite springs, which graduate up from that in steps to over 400lbs/inch. BTW, the stock rear spring probably SHOULD be about flat with a full tank of gas and a couple of passengers (ride height in the rear is adjustable via the outer rear spring bolts). What I'm trying to say is that the aftermarket stuff is aimed at handling and not at comfort, and Chevy chose 200lbs/in for a comfortable touring suspension, 300lbs/inch for performance.

GM has, I believe, Delco gas shocks recommended to replace midyear shocks, or you can go with an adjustable gas KYB or Bilstein or Koni, adjusted to the soft positions.

Replace all your suspension bushings and cushions with new stock rubber bushings (don't forget the A-arm and trailing arm bushings and the differential nose cushions as well as shock and sway bar cushions) for best comfort & least vibration. Tires are very important to riding comfort as well... I've heard Pirelli P4000 are excellent touring tires that I think can be had in hard-to-find Corvette sizes (205/75R15 or 215/70R15) at reasonable prices, as can the more expensive Michelin MXV4, and I've heard Coker Tire still offers a remake of the older Michelin X. High-speed balancing is a must, and have the alignment checked front & rear, altering front toe-in settings to accomodate the radials.

Vette Brakes & Products has a good selection of suspension parts http://www.vettebrakes.com as does Van Steel http://www.vansteel.com (get a catalog) and Long Island Corvette http://www.licorvette.com and other vendors.

 

[Tom Bryant]

Wayne is on the right track here. I put 215/75R15s on my '67 big block coupe and it made a new car out of it . Rode and drove much better. Still had the front weight bias problems associated with a big block but you don't have that with a small block car.
I ran these same tires (might have been 205s) on my '65 300 hp convertible and it was a dream to drive.

I had an outer spring bollt break or the nut broke: not sure. never found it. The main leaf hit the road and twisted so the spring was junk. Got a F41 7 leaf from a friend for $10. The car handled much better when pushed but I paid the price in the ride department. You could feel every ant crossing the road.

Bottom line is if you want a comfortable touring car stay with the 9 leaf, rebuilt with new liners, 205 or 215 radial tires, the recommended replacement gas charged shocks and replace all of the old worn and hard suspension bushings with new rubber ones. The poly bushings will give better handling but they will transfer more roughness to your body.

These 300 horsepower 4 speed and 3.36 rear gear cars are great distance drivers. I would say my '65 was my favorite mid year car for going down the road on a trip.

Tom

 

[JohnZ]

My '67 327/300 4-speed 3.36 convertible now has all new (rubber) bushings everywhere, stock springs (rear rebuilt with new liners), KYB "Gas-A-Just" gas-charged touring shocks, 205/75-15 Coker redline radials and a fresh Hunter laser 4-wheel alignment; drives like a new car again, but much better due to the radials - terrific highway cruiser, nice ride and handling.