I was thinking of changing my motor mounts to the new poly mounts ,I am putting in a 95 3.4 camaro motor with a 40t60,or 440t4 trans,with a mild cam and some porting done to the heads and intake.
I have heard that the poly motor mounts can cause the car to vibrate a little more.
I am rigid mounting the cradle on this 87 gt with alumnium mounts .
Any advise in this area would be great ,should i poly mount the motor and trans or will rubber stock mounts be just as good for this swap.

Either way get new ones.
I am currently changing to poly to minimize any movement that could affect the rear suspension handling.
I noticed more vibration using solid engine mounts but with high performance engines it is the way to go...
Comfort vs. Performance - its a personal preference, so there is no wrong answer to your question.
Your swap sounds nice.

Ryan

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1986 Fiero2m8 (LT1 NOS / 4T60 Auto)

I can speak from experience. My 88 Mera was an automatic when I bought it. I put in a poly dog bone. It vibrated when you were in gear at a full stop. Any other time it you did not feel anything. I later changed to a Getrag 5 speed manual. At a full stop there was no vibration. I even made the one end of the poly dog bone solid aluminum. Still no vibration. I miss that vibration. Made the car feel powerful. I miss that vibration.

"I'm pickin' up good vibrations....."

Yeah, I just put Rodney's poly tranny & motor mount in my car (Getrag, turbo V6) - wow what a difference!
Has a whole new "feel" to it. More sensory input for sure (uh, it vibrates!).
WAY more solid feel when driving.
No slop or mushiness now (and I had new rubber mounts before).

I'd highly recommend them (Rodney's that is, vs... well... the "other" ones).

quote Originally posted by gofast250: I was thinking of changing my motor mounts to the new poly mounts ,I am putting in a 95 3.4 camaro motor with a 40t60,or 440t4 trans,with a mild cam and some porting done to the heads and intake. I have heard that the poly motor mounts can cause the car to vibrate a little more. I am rigid mounting the cradle on this 87 gt with alumnium mounts . Any advise in this area would be great ,should i poly mount the motor and trans or will rubber stock mounts be just as good for this swap.

use rodney dickman's transmission mounts, and darrell morse's engine mount, unless rodney has an engien mount that he sells now. they are a tad softer than the wcf mounst and dont vibrate nearly as much, but still give MUCH better support than the stock rubber mounts.

also, dont use the aluminum cradle mounts, use the poly mounts instead, a tad softer, but still much better than the factory rubber..

quote Originally posted by gofast250: I was thinking of changing my motor mounts to the new poly mounts ,I am putting in a 95 3.4 camaro motor with a 40t60,or 440t4 trans,with a mild cam and some porting done to the heads and intake. I have heard that the poly motor mounts can cause the car to vibrate a little more. I am rigid mounting the cradle on this 87 gt with alumnium mounts . Any advise in this area would be great ,should i poly mount the motor and trans or will rubber stock mounts be just as good for this swap.

If your using the auto trans--first hand--with a 3800sc I can say you will feel the vibration more, with a 3.4 I`m not sure how much, it is preference, in my case I`m changing back to custom stock rubber mounts, if you can get to a Fiero show and drive a couple with poly & rubber , it may help make your decision a little easier, I`m pushing 50, so the softer the ride the better, like said above--its preference.......

Wow ,Thanks everyone ,Like you guys said ,I guess I can go either way
I think for now the rubber stock mounts will be easier on the pocket if they are going to work just as good ,I can due with out the vibrations for know + i building this for my wife ,As if i were going to drive a auto ,I will live the poly mounts for my 88 5sp.

aaronrus ,Why not soild mount the cradle ,just like the 88s

I just started driving my V8, it is solid mounted to the cradle and the cradle is solid mounted to the frame.
If you dont have any ballance issues it shouldnt be fine with the poly.

I got all poly motor mounts in my 3.4 S/C car. Got them from west coast fiero. When I first put them in I think I lost a filling in my tooth from the vibrations. It let off a harmonic vibration inside the car that was like no other. I still dream about that sound That smoothed out after 1000 miles. I love the way they keep the motor where it is supposed to be. I like them so much that I am going to be using all poly on my "VERT" build.

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88GT 3.4SC
88GT T-TOP
87GT VERT (build in progress)
www.fiero.nl/forum/Forum1/HTML/053203.html

i personally liek a v8 grumble, but i dont liek uncomfortable vibration.. rodney's mounst combiend with the prothane cradle mounst are the best way to go..

[This message has been edited by aaronrus (edited 02-23-2006).]