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- The 1967 - 1972 Chevy/GMC Suburbans & Panels Message Board (https://67-72chevytrucks.com/vboard/forumdisplay.php?f=38)

- - How much sound insulation? (https://67-72chevytrucks.com/vboard/showthread.php?t=705235)

Re: How much sound insulation?

Quote:

Originally Posted by vectorit (Post 7579597)

I tend to believe this.
I run twin FM series 70's, and they are nice at idle.
But at highway speed, they tend to drone.

I would like to replace them with a same size muffler from Magnaflow, but it seems all they make are much smaller mufflers even if they are quieter.
Trying to avoid making my exhaust system look like a patch work of welds.

You might try the "J" pipes before you replace them. I put them on the Panel Truck with the Flowmaster 40 knockoffs and it made a lot of difference on the drone....

LockDoc

Re: How much sound insulation?

We always apply the spray on sound deadener after the vehicle is painted. This way we can paint all the way into the cab with overspray and then make a nice looking finished product with the spray in sound deadener. We use a product called VB1X from Cascade Engineering. You can find it on www.partsexpress.com

I always use the same process on all of our builds. All of this is after the vehicle has been thoroughly seam sealed and epoxy primed:

* Mask vehicle
* Apply 3 coats of VB1X to the interior surface of any unpainted part.
* Apply HD Matt from Cascade Engineering to floor and roof- this product comes in either sheets or rolls and is placed in pieces. You don't need to cover every square inch. Basically, it is installed on the flat pieces. You are just changing the frequency pitch of the metal surface.
* Jute matt
* Carpet
***Enjoy :-)