From their website:
NEW UPDATE 6/6/2005!
We now have an even softer Polyurethane for our custom Motor Mounts! It is tough enough to withstand low 10 to high 9 second passes on the strip year after year, yet still flex just enough to keep vibrations to a minimum and NOT set off the knock sensors. We are using these newest "soft 70" Poly Bushings in all of the Production 3.8 G-Body mounts (Turbo Regals) and in the Production 3.8 motors in the '89 Turbo Trans Ams (TTA's).
The TTA's previously had a bit too much vibration transferred to the chassis on some cars. These softer bushings should reduce vibrations felt in the car to a much more acceptable level on ALL cars. If any TTA owners are looking for replacement mounts for more of a bone-stock (lower HP) application, PLEASE just let us know when ordering. We can set the frame pads and/or mounts up specially for different HP levels to keep vibrations on each specific car to a minimum. The TTA's have NO body bushings like the G-body's (Turbo Regals) do, so they are more susceptible to transfer every little vibration right into the chassis. Since we came out with these mounts, we have strived to make them work as best as possible, even though the qty level they sell at doesn't really warrant the time/expense. Just one more way we strive for 100% customer appreciation! These new versions should put any previous concerns of vibrations to rest for new customers. We are looking into offering rebuild kits as well, but probably easier to sell existing mounts to someone racing more, and then just get a new set for street/strip use.
Our Stg II Mounts (for 3.8/4.1 Prod & Stg I & II) in G-body chassis are now assembled with our "old" soft version 80 duro Poly bushings for most applications. These seem fine down to high 8's and plenty of daily driving. For faster cars that race more, we can put them together with a "medium" 88 duro to handle more power or 7 sec passes year after year. Just let us know your power/performance level when ordering, and we will be glad to custom tailor a set for you at NO additional cost. All mounts from approx mid 2003 & on should have their durometer rating (70, 80, 88, 93) written on them.
So, to recap all the "poly stiffness" issue:
70 Durometer = currently softest available, daily drivers down to approx low 10's, black in color. Not available before June of 2005, currently in all standard production 3.8 mounts (# 0101, 0102, 0103, 2000).
80 Durometer = Was considered "soft" from mid 2003 to mid 2005, red in color. Good for Heavy Duty versions of prod 3.8 mounts (# 0101-HD) and currently all standard Stg Mounts (# 0104).
88 Durometer = Briefly considered "soft" in early 2003, early ones were black in color (only a small group). Most of them (and currently) are red in color. They were later considered "Mediums" when the 80 duro came out. These are used very seldom now in extreme duty Stg Mounts (# 0104-HD) that are more race-only setups down to the 7's. They also work fine on daily drivers in the 9's and 10's, but may be a little more harsh feeling. Still better than the first ones made.
93 Durometer = Original bushing that came in all mounts, black was only color available. Basically as softer versions were obtained (took many months & lots of $$$), they were only used on the Stg mounts or faster cars. Sometimes only used on Drivers side, and the softer 88's were used on the Pass side. Completely phased out by Sept 2004 and no longer needed at any performance level. There is absolutely nothing wrong with the older mounts/bushings other than they were a little too "heavy duty" for some people.
