Exactly, but not move so freely that the exhaust loses its pulling/scavenging effect...

 

Stock is 2" from the manifolds, to the cat.... for the most part. 2.25 to 2.5 there would be of benefit. At LEAST 2.5 inch the rest of the way back, if running a single pipe..... preferably 3".... If going to true duals, 2.25 or 2.5 inch end to end would be good.

 

my headers and bolt on magnaflow setup is 2.25 from header flange (which is actually closer to 2.5" opening) to the cat and 3" after the cat....I never had stock setup so dont have a fair comparison to compare it to...but it seems to flow well..

 

And we probably are going to be unable to convince you to put it on the dyno, test it, then put the exhaust back to stock, to compare, are we.

 

It had pacesetter shorties and a magnaflow exhaust on it when I bought it... (which both rusted to point of failure) and I replaced them with stainless all the way through...)
I will recommend the eastwood internal header coating spray... it works good to keep temps down... my new stainless headers have barely shifted color at all with like 500 miles on them so far... It comes in a spray can with a special long hose with a nozzle at the end to coat the insides of the header pipes... seems to work like ceramic coating only from the inside out

 

i got them for cheaper, thats the only reason I got them. What if i just got a magnaflow hi flow Cadillac converter with the same size pipes instead of 3 or 2.5 inch pipes going to my cat?

 

Haven't heard someone call it a Cadillac converter in a long time lol...
It's a catalytic converter, nothing to do with Cadillac.
You can use whatever fits, but 2.5"-3" will yield better flow with single outlet pipes. Using less will restrict it = less power.

 

I'm not very smart, do u know any brands that offer a direct fit catalytic converter with 2.5 inch pipes?

 

My butt dyno loved the improved acceleration, I still gotta get an aftermarket y pipe too.

 

Magnaflow makes a direct fit, that flows better than stock. Used in combination with some shorty headers, there will be a difference you can feel.