I've been guarding this secret for a few years now, but I'm gonna let it out of the bag.
When I lowered my 67 C10, I wanted to find a low cost adjustable panhard bar, or perhaps make my own...
But first a little background... I was a professional mechanic / shop owner from about 1986-2002. One of my areas of specialty was wheel alignment and suspension. During that time, the FWD Pontiac GP, Chevy Lumina/MC, and Olds Cutlass were in their heyday, so I aligned hundreds of those cars.
… back to the C!0: When I looked at the size, and mounting hardware of the C10 bar, I thought to myself… “that looks very similar to the rear control arm of a Grand Prix”. I just so happened to have a wrecked one nearby, so I did some measuring… Paydirt!
The rear toe setting for the Grand Prix is accomplished by a turnbuckle style adjustable rod that Is the same length and size as a C10 panhard bar. The only modification that is required is to drill the center bushing sleeve hole on each end out to the required 5/8” diameter (make sure you use a good quality drill bit, because that is a hard little bushing that gets hot fast).
The only reservation I had was that the Grand Prix bar is hollow instead of solid, but after 3 years and 13,000 miles of some very “spirited” driving, powered by a healthy LS6 (400+ HP) and 3.73 gears, I’ve had no issues whatsoever. (It would take a situation outside normal operation to create a force on the bar that would tend to bend it anyway).
There’s plenty of adjustment for the 5” drop that I went with.
These can be had for $10 from a junkyard in my area… and there’s plenty of them! Look for a 1997-2008 Grand Prix, Lumina, Monte Carlo. Be warned to take a 1" and a 15/16" (or metric equivalent) open-end wrench with you and make sure the jam nuts/sleeve aren’t frozen before you buy. It was very common for those to freeze up beyond repair - especially on Northern cars. I think the end bushing wrench size you’ll need is a 15mm and a 18mm, but not 100% sure… take a 13mm and 21mm too.
New versions can be purchased for under $25. The Moog part number is RK660276, and the AC Delco number is 45G36010.
