[ck67goat]

Starting a project for a 67 GP restoration and looking for upper and lower front control arm bushings, preferably polygraphite or any other lubricated urethane type bushings.
After searching usual places, only the one rear lower oval bushing is available in polyurethane from OPG. Does anyone know if such bushings are produced or whether another bushing is interchangeable?

[JLMounce]

These fell out of favor after their popularity in the late 90’s and early 00’s. The idea was sound, impregnate graphite into the poly bushing to stop the squeaking. In practice, it was discovered that the graphite physically ate away at the polyurethane bushing.

PST I believe still sells graphite impregnated poly bushings so if you’re after that, you may try them.

My philosophy is that Poly is kind of a bushing material that doesn’t actually solve a problem. If this is a street car and NVH is a concern, you go rubber. If NVH is not a concern and you care more about handling prowess, you go delrin.

Poly sits in the middle providing some deflection resistance over rubber, but having a propensity to be noisy, so you deal with weird outward sounds. Delrin is not outwardly noisy but will transmit some amount of NVH through the suspension, into the chassis.

I have two cars with Delrin bushings and quality and type of bushing matters. My bird with SPC arms has quality Delrin bushings that utilize a lot of the nylon material. They don’t actually transmit much NVH over the previous polygraphite bushings I had in the factory arms.

My wife’s Chevelle on the other hand has the summit branded arms that contain cheap, thin Delrin bushings. Those arms transmit a lot of harshness specifically through the car.

Long story long, if handling is a bigger concern, go with a quality Delrin bushing. If ride comfort is more of a concern, go with a quality rubber bushing. Leave the poly stuff to bouncy balls.

[ck67goat]

Good to know Delrin is now the way to go. Looks like Summit lists a couple vendor options I did not see before. Thank you for your help!!!

[Scott65]

Originally Posted by JLMounce

These fell out of favor after their popularity in the late 90’s and early 00’s. The idea was sound, impregnate graphite into the poly bushing to stop the squeaking. In practice, it was discovered that the graphite physically ate away at the polyurethane bushing.

PST I believe still sells graphite impregnated poly bushings so if you’re after that, you may try them.

My philosophy is that Poly is kind of a bushing material that doesn’t actually solve a problem. If this is a street car and NVH is a concern, you go rubber. If NVH is not a concern and you care more about handling prowess, you go delrin.

Poly sits in the middle providing some deflection resistance over rubber, but having a propensity to be noisy, so you deal with weird outward sounds. Delrin is not outwardly noisy but will transmit some amount of NVH through the suspension, into the chassis.

I have two cars with Delrin bushings and quality and type of bushing matters. My bird with SPC arms has quality Delrin bushings that utilize a lot of the nylon material. They don’t actually transmit much NVH over the previous polygraphite bushings I had in the factory arms.

My wife’s Chevelle on the other hand has the summit branded arms that contain cheap, thin Delrin bushings. Those arms transmit a lot of harshness specifically through the car.

Long story long, if handling is a bigger concern, go with a quality Delrin bushing. If ride comfort is more of a concern, go with a quality rubber bushing. Leave the poly stuff to bouncy balls.

Ditto this.
I had poor service life out urethane/graphite. Delrin is a proven performer, and set up, and serviced properly is a winner here. If you're after performance improvement anyway.