4-Speed Transmission Mounts - Difference?

[jeff68]

The 4-speed transmission mounts available from the usual suppliers state that they are good for all 67, 68 & 69 4-speed cars.

However, looking through the parts books, it seems that there were 3 different mounts:
3870182 = 67 all ST
3928392 = 68 - 69 all ST with 230, 250, 327 & 350
3895830 = 68 - 69 with 302 & 396

Does anyone know the differences between these mounts?  Just wondering if there are dimensional differences or just differences in rubber compound.

Is there any problem with using a 3895830 on my 68 327/275 with a M20 4-speed?

[big iron]

Jeff,
I tend to agree with your assessment that there is a difference in rubber compound. Looks like in 67 there was a mount problem in the high HP cars so they redesigned the mount for 68. Do not think there would be a problem.
Bob