Polyurothaine Engine Mounts. Yes or No? Pros & Cons?

Ok, I am about to do a complete exhaust and while I have the manifolds out I wanted to replace the factory mounts with new Prothane Polyurethane mounts.

Someone recently told me NOT to because the car was my daily driver. What are the pro's and con's with these? Are they that bad for a daily driver? What should I expect to experience?

Thanks for ANY and ALL information that you can provide.

I just recently installed prothane motor mounts while I was installing my LT headers , which IS the time to do it as it allows you the most room to work.The motor mounts are a little bit of a pain in the butt because once you get the stock mounts off you have to drill/grind the factory rivets off in order to separate the two halves of the mounts,then heat the mount up a little bit with a torch to remove the stock rubber mount.Once that is done all that is left is to lubricate the prothane mounts with some WD-40 or what ever your favorite lubricant is,place them in the steel brackets and bolt the two halves back together and install them back on the engine block.As far as the pros and cons: the pros are your engine will now be almost rock steady so your headers and exhaust won't be hitting the floorboard or anything else which the knock sensors might detect and retard your timing.The cons are this is a time consuming job , but one that you will be glad you did when you had the exhahst manifolds/ headers off.If you have someone helping you the job will be alot easier and in my opinion was a mod that i'm glad I did!! Hope this helps.:)

Why did you use WD-40? I've never heard of anyone doing this before. Did you use the black graphite impregnated ones?

Why did you use WD-40? I've never heard of anyone doing this before. Did you use the black graphite impregnated ones?
The lubricant is just to help the steel halves slip over the prothane mounts so that the two halves can be bolted together, it is not necessary but it sure makes it easier!:)

Thank you SO MUCH for the info. I am glad I didnt just listen to one person and sell them.

Thanks again everyone!! Now to get the True Duals and Headers so I can start the install!!

The lubricant is just to help the steel halves slip over the prothane mounts so that the two halves can be bolted together, it is not necessary but it sure makes it easier!:)


Gotcha. Did you use the supplied bolts? I have the prothane bushings ready to go on, but I was debating on buying some grade 8 bolts. It just seems like with the motor torqueing hard on the bolts all the time, it might be nice to have some added insurance.

i went to Prothane poly mounts when i did LTs on my LT1. they were very simple to rivet off and get out the old ones. id recommend it to anyone whos gonna be that deep into the engine bay. good luck

Gotcha. Did you use the supplied bolts? I have the prothane bushings ready to go on, but I was debating on buying some grade 8 bolts. It just seems like with the motor torqueing hard on the bolts all the time, it might be nice to have some added insurance.
No I didn't use the supplied bolts for two reasons:1- they put 5/16 bolts and 3/8 nuts (i think someone was smoking something)2- I thought the same thing you did so I bought grade 8 3/8 bolts with nyloc nuts.:D

So you recommend getting the Grade 8 3/8 bolts with Nyloc Nuts? I should be able to find that at a hardware store right? If not where is the best place to get a set of these?

So you recommend getting the Grade 8 3/8 bolts with Nyloc Nuts? I should be able to find that at a hardware store right? If not where is the best place to get a set of these?
I got them from a local mom and pop hardware store.:cool:

The supplied hardware is only there to hold the half together until you install them. The three big factory bolts are what hold everything together.

The supplied hardware is only there to hold the half together until you install them. The three big factory bolts are what hold everything together.

It still sounds like a good idea to me, because the motor is putting stress on the bolt that goes through the bushing. The bushing then puts pressure on the clam shell. It seems like there would be quite a bit of stress on the supplied bolts.