[pdtweeks]

Originally Posted by mikedsilva

My motor is a 3.0 with the larger port heads, ITBs, 10.2 compression, webcams, Georges Euro headers.
I've just acquired a GT3 muffler.

Here are my questions:
- Being a 3.0 still, I imagine just the 'quiet' ports are all I need to use?
- on original GT3, what diam are the pipes leading into the muffler? 2 inch and 2.5 inch?
- on original GT3, does the car always run through the quiet pipes but then ONLY open the loud pipe when you hit the switch? Or did it open the loud pipes depending on vacuum and load?
- the collector on my headers is 2.0, and from what I can ascertain, the input diameter to the quiet port on the muffler is also 2.0.. so is it prudent to simply use 2.0 inch tubing from the header to the input of the quiet port? or is there any gain to using 2.25 and stepping down to 2 inch at either end?
- looking at pictures of the valve arrangements online, it appears that both the pipes that connect to the muffler, protrude quite a bit inside the muffler. Is that correct?

Cannot think of anything else to ask just yet.

Mike,
I can verify the that the inlet sizes on the GT3 muffler are 2" upper (quiet) & 2.5" lower (not-so-quiet). And they do protrude into the muffler a bit...the gaskets design requires this.
pd