5/16 iso thermal. I paid about 205 for mine new best thing I did to my 06 A/T. The other was rear diff

 

Ok thanks! Where'd you get that price???!

 

And the isothermal right? Just asking because I read that the copper is the best.. No matter what temp.

 

I got it off eBay from seller ocinfiniti I do a lot of stuff from him so check him out. I just looked on his store and he has all of them for the best choice.

 

lol way to bring back a twp year old thread :-)
At least if people search google for it they can have updated answers in a sense.

 

At the dyno shop i go to people have the Blox spacers that are less than 100$ and they put up just as good numbers as Motordyne. Now obviously if youre doing the manifold spacer then the ISO makes sense,but if youre just strictly doing the plenum spacer, from what i have seen first hand, the blox is just as good. It in fact is made out a poly thermal material completely, where as the motordyne just has a removable gasket per say that lays on top of the spacer.

Might be wrong,again this is just from what i have seen at the shop and hear from the tuner

 

I do know the 5/16" seems to make the most power on non-Rev- up motors.

I don't think the "Butt Dyno" wouldn't be able to discern the ISO-thermal spacer. The one that goes on the lower manifold.

 

Just ordered my 5/16 Iso!!