Originally Posted By: IndyIan
Well I put in my 76A polyurethane dog bone mount a couple days ago.
The good is that it does stop most of the engine rotation, which makes the car much nicer to shift, both in hard acceleration and rev matched down shifts. No engine flopping either when you get on and off the gas in lower gears.
The bad is the extra noise and vibration in certain situations. Fortunately its almost unnoticeable in top gear, just cruising to work. But starting the engine and taking off in 1st below 1500rpm is a bit loud, and WO is noisier too.
Maybe it will "break in" a bit, but I doubt it will change much even in warmer weather as polyurethane doesn't change too much in hardness over ambient temperatures.
I may play around with it and drill some holes to soften it, but for now I'll leave it and see what happens.
Maybe I have got the 76A one?
Mine has quieted down significantly.
The dash rattles a bit more on the cold mornings from the dash plastic being so hard ... It's always done that, but seems to be a bit more with the poly mount. The only time it really annoys me is if I'm cruising along at 30 or 35 in 4th gear and come to a big hill. Then I just drop down to 3rd to raise the revs above 2000 and it's good.
Do you notice that clutch modulation seems to be easier since you can now "feel" clutch engagement? I barely have to give it any gas to take off now. Maybe enough to get the engine to 900RPM and that's it! Definitely feel it, though, when the clutch bites at 900RPM.
It REALLY makes a difference in the performance of the car. Even increase in noise, it's a change for the better.