Edelbrock cat-back: Conflicting descriptions

[good2Bking]

OK, I think I've finally settled on a cat-back and I like what I've heard from Edelbrock sound clips (plus that price is hard to beat!) ... I'm a little confused about the pipe size though, and I'm hoping someone who has one can clear up some stuff.

Summitt and the Edelbrock site say the muffler is a 3" in and dual 2.5 outs. I read a review somewhere online (I think fbodyv6) that said the I-pipe tapered off to 2.5" before it enters the muffler. Assorted archived posts say the I-pipe is anywhere from 2.25" to 2.5" ... what is the real story?

Also, is this system stainless steel, or aluminized? The Edelbrock site says the RPM series muffler is stainless steel, but doesn't say anything about the pipes. Summitt says it's aluminized steel.

(I'm also planning on sticking with the stock tubular manifolds and Y-pipe for now, and installing a new Catco 3" in and out, if anyone has any comments on this setup.)

[whtefbrd96]

Ok in order to do what you want a 3" in/out catco you will have to get a shop to make you a 3" S-pipe and a 3" I-Pipe into the edlebrock over axle pipe which is 3 inch and into the muffler and out with 2 2.5 inch pipes, then i had my shop weld on some 18"long 3.5" slash cut tips ........ sounds GREAT not tooo loud and not ricey. I think with tips catback and the catco including install i spent around $450. and the pipes are aluminized and the muffle is stainless i have no rust anywhere and a LITLE bit of discoloration on the muffler where the inlet pipe is. for the price and sound i dont think it can be beat !

[good2Bking]

Thanks whtefbrd96, but if you had the shop make you 3" S- and I-pipes, why buy a cat-back system? Why not just buy the right RPM series Edelbrock muffler?

I still didn't get what size pipes the Edelbrock cat-back comes with ... if anyone else can help?

[TrixTeR]

he did just buy the muffler.... he said his shop made up all 4 of the pipes to go with it.

[whtefbrd96]

because the "catback" is only the over axle pipe muffler and the two tail pipes :rolleyes: but thats what most are and the over axle pipe is mandrel bent and i think it would be a litle time consuming for a shop to make that so it wouldnt ratle...

[good2Bking]

Ah ... thanks for clearing that up. I didn't realize that it didn't come with the S- or I-pipe.

[darkthoughts5000]

ok, heres my situation, i got the edelbrock and 3"in/3"out cat. the mufflershop had to make an s pipe and an i pipe. yes, the cat back tapers from 2.5" near the cat, to 3" down... but the tapering is only about 1-1.5'. almost seemed pointless to me but then i thoughts about backpressure and all that... got a little more logical (not much, but good enough for me). it is aluminized steel, so you probably wont have to worry about it rusting out for a while unless you live in an area that puts salt on the road everytime it snows. then some years down the road, take a look to see if theres any rust. oh ya, almost forgot to mention, the muffler shop also needed to weld on an adapter from the y pipe to the cat for obvious reasons. usually goes unsaid in exhaust topics because of their obvious nature, but just thoughts id be one of the few that actually threw it in there. hope it was informative.