I took my car on the freeway and at 55 mph i start having a vibration coming from the under car ... my first tough was that my i needed to balance my driveshaft but i need more info before ... i put a 427 chevrolet in my 86 iroc and one guy was explaine me that my shaft can be to long .... but i dont know how to check that

i need help plz

The 427 by itself makes no difference to driveshaft length, because all the extra length of the engine is added forward of the mounts.

Whats your pinion angle?

Forget this wild goose chase.

any chance your wheels need balanced? Also when I started chasing my vibration issue I read the stock steel driveshafts aint to great. I bought a inland empire aluminum one, it helped but I think my issue is in the axle.

Not a wild goose chase if it fixes the problem. I had a vibration that started at 65 mph. Lowered the transmission mount fixed it. (ES trans mount and used the plate they claim you must use, removed it)

Now if I used the wrong terminology, Im sorry, but it fixed my problem.

Does this weaken the mount at all?

From all the posts that I read, not one has had any issues without it. That's all I can say.

How do you remove the plate?

Im talking about the one that just gets sandwiched between the mount and the crossmember. It just bolts in with the mount.

ah, so it can be easily removed. I might actually try that.. Thnx