I'm looking into getting QTP headers and their y-pipe with Carsound cats sometime in the next couple of months and I figured it would be a good time to put in poly motor mounts and trans mount. I decided to do this because some people complain that their headers or y-pipe bangs into the floor. Now I'm not sure if I should do this or not because of complaints about false knock and excessive noise from using the poly trans mount (not sure if poly motor mounts also cause this problem). Should I keep the stock rubber or use poly? Or should I use a combination of the two like poly motor mounts and a 1LE trans mount? My dad has a 68 big block Corvette that he put poly mounts on (motor and trans) and you can't tell a difference from stock. Sorry if this has been discussed before, but I didn't have much luck in my search for information. Thanks for your help.

 

i know i have a bassani offroad ypipe and it hits the frame right under the driver seat.

i'm putting in some poly motor mounts soon as they arrive cause from what i've read this should fix the problem.

i've heard mixed reviews on the trans mount. but based on what i've read, the 1le is the middle ground...stiffer but not too much to cause too much vibration

and i've never heard of the poly mounts causing knock.

summit has the poly mounts for $40 but they are backordered, i just ordered mine from thunder racing for $50

 

I'd personally suggest against the poly mounts. I had placed a poly trans mount on my old 97 Z28. It was 1/4" taller than the stock mount, which changed the pinion angle from the output shaft of the trans. It also gave a very nasty vibration and resonance that could be felt throughout the car. The vibration/ resonance disappeared when I switched back to the stock mount. This might be minimized by also changing the motor mounts.... or it might amplify the resonance. The poly mounts are much stiffer, so......

Granted, I'm talking LT1 specs here, but I had no increased vibration from a LT header setup and stock engine/ trans mounts. From this experience, I'd stick with what you've got.

Schantin
1997 Camaro Z28 (some mods) SOLD...due to the A4 tranny.

2002 Camaro Z28 M6