solid vs. poly motor mounts

[69projectKAOS]

what do you guys prefer ?? my i have a 355 solid roller with a th350 trans approx 400hp , but will hopefully be converting to tko600 or t56 soon if that matters. let me know .-Dom

[wmhjr]

Solid. Period. I had some MityMounts and replaced them with solid mounts. I was afraid that I'd have uncomfortable vibration, but frankly they have been superb. And I'm running a 462ci 11:1 stroked 600hp pontiac with a TKO600. Absolutely no down side that I can determine.

[69projectKAOS]

that`s what i was worried about with the solid mounts, do they raise the motor up because i have read that some do. what brand do u have? -Dom

[wmhjr]

Mine did not. I got mine from Butler Performance (remember, I've got a pontiac). I asked before ordering and was assured that the geometry was identical, and it sure appears to be. I actually wanted to slightly raise mine, so I made two thin places for between the crossmember and the lower mounts.

I was VERY nervous because my motor sure isn't subtle. Yet to be honest I've completely forgotten that they're solid until I think about it - and they're way stronger.

[69projectKAOS]

OK good, because i definitely need the solid mounts, when i took the motor out last time the passenger side mount was in two pieces! the rubber separated itself from the lower mount. and that was with the stock 350 and now my motor was rebuilt and bored.60 over and a bigger cam and different heads, so it is now pushing about 400 when we had it on the dyno. also how do you like your tko600? and where did u get it .-Dom

[JChilders]

I have a 350ci with about 400hp and pooly mounts. I have about 9000 miles on the car and I have had no problems at all.

I also have a TKO600. Its one of the best upgrades I have have done yet. If I baby the throttle I can managed to get about 25mpg.

[Scott Parkhurst]

They don't all have to be the same, either.

I run a solid mount on the driver's side, a (new) stock rubber mount on the passenger side, and a poly mount on the trans. Plenty strong, minimal vibration transfer.

[CarlC]

Modern polyurethane and stock-type rubber mounts have an interlocking feature that keeps them from coming apart like the early 60's versions.

Solid is fine for either the motor or the transmission but not both. There needs to be some flexibility or else there is a high probability that the transmission tailshaft housing can break.

[6'9"Witha69]

I run solid motor and poly trans mounts. You will notice if anything is out of balance right away! But when everything is working (balanced), they are great. One less thing to worry about breaking. That and with headers that fit close to a steering box you know they will not hit due to tq twist pushing a tube into the steering box.

[Rybar]

Anybody else running solid motor and tranny mounts? I've gone through 2 sets of poly motor mounts and 1 poly tranny mount and can't figure out why. Am going to swap over to solid and looking for opinions.

[317millhand]

Solid motor mounts with poly trans mount is always a good combination. Just never run solid motor and solid trans because you will break something.

[Taman]

On a 2nd gen F body, clam shell motor mounts are used. All most impossible to break. I had a 455 in my 75 TA with 575 hp.. I used the poly inserts in my stock clam shell shell. Worked awesome. Instead of the shaker shaking, now the whole car shakes. I have found the stiffer I makes things, the more rattles that pop up.

[ed1le]

My buddy has solid eng & trans mounts in his '69 Nova. It vibirates the heck out of you. I really think swapping to a poly trans mount would take care of it. I'm running poly mounts now and had them in my '91 Z & '70 Chevelle without issue.

[Vegas69]

I like solids for racing but they aren't that great for cruising. You will feel all the harmonics. Some of the big block guys use a solid on the pull side and a rubber on the other.

[Scott Parkhurst]

Some of the big block guys use a solid on the pull side and a rubber on the other.

Some small-block guys do too! LOL!

A solid won't break, and a rubber will absorb harmonics. I've been running them this way for many years in many different cars. It works for me!

[rich_fbodySS]

I've been running solid motor mounts in all my cars since the 80's.
(currently w/poly transmission mounts).
No downside I could ever see, and never had to replace one.
-Rich

[Rybar]

Thanks guys, going to switch to solid motor mounts and get a new poly trans mount. Not sure why my car keeps killing poly motor mounts??

[Vegas69]

Are solid mounts a good idea with a knock sensor?

[Procharmo]

How about stock mounts with a motor plate and adjustable pre load on connecting rods from the frame to the motor mount....



Seems to work so far!!!!!

[Jasons72]

Swapped out to solid motor mounts and will never go back, i love them!