first....regarding the tranny mount, i really wanted to go with poly on this but after reading so many with vibration issues and so many w.o vibration issues i just know my luck is ill have those issues. I think stock may be the best choice. however whats the best stock brand to get? rockauto lists DEA or westar.or is another brand better? for the record i am going from a 305 motor to a 350 motor that will only be built for 300-350 hp tops.

for the engine mount question: i want to do poly with this but will poly engine mounts make vibrations or is that only the tranny mount that will cause that?

 

I have a 87 coupe and 2 yrs ago I went from a 305 to a 350 with approx 315 hp with a built 700r4. I installed poly bushings on all 3 mounts and have not noticed any vibration issues. I have also replaced all suspension bushings with poly.

 

what brand did you use?

 

I have Energy suspension bushings everywhere. I haven't noticed any undesirable vibrations. But I suppose it really depends on what you are expecting and how smooth and quiet the rest of your setup is. My car goes down the road smoothly and without any undo vibration. But then again I have a bit of gear noise, valve train noise and did I mention exhaust noise? It aint a Cadillac but it doesn't ride like a work truck either. If you have a relatively stock vehicle and want super quite smooth operation then the stock type mounts and bushings are probably best. Moog makes good parts and are available at a good price through Summit.

 

Energy Suspension

 

Did you need to take the "plate" out like most people ?

 

No I did not, I think it is due to me changing motor and trans mounts at same time. Now granted like the other reply, I have headers with a 3'' Magna Flo exhaust and I do get some whinning from my 9 bolt rear end but I do not notice any abnormal vibrations.

 

Eight years ago I installed Energy Suspension motor mounts. Not a easy thing to do.
I could feel the engines rhythm a little more and that's what I like. About a year ago I tried to install Energy Suspension trans mounts. I tried two different ones then gave up.

After tearing another rubber one I decided to try again and finally found one that worked.
Energy Suspension # 3.1108G without the preload plate.
I have not experienced an increase in vibes.

I'm really glad its finally there. No more tore cheap rubber ones.