I have a 1999 ECSB 5.7L Silverado with mods listed in sig. I'm ready to change up my exhaust a little and was wondering which would give me the best performance and sound. The truck from the factory is true dual into the muffler and one outlet. I have a dual in/dual out Super 40 at the moment.

So here's where we begin. I got a hold to a factory Y-Pipe for this year truck and I will be cutting the cats off and welding in some pipe in place of them. As far as the flange at the end goes I have laser cut two new ones so that the holes will be the same size. (One is bigger due to the converter.) So should I leave it true dual and run 2 mufflers with an H or X Pipe, OR make a Y-Pipe and run maybe 3 inch into one muffler? I have shorty headers and Im wondering which setup will give me a good sound but keep the performance I currently have. Thinking about going with Magnaflow this time, but I'm open for suggestions. Thanks

 

ditch the shorties for a set of LT's, lose the cats like youre already planning on doing and to save money on pipe and mufflers go with the y-pipe to a single 3" magnaflow. And sometime down the road if you really want to see some more power out of it lose the hypertech and find someone to custom tune it. just a few suggestions

Zach

 

I bought the headers a while back like almost a year ago and had them ceramic coated and put them on about 2 months ago. It kinda sucked cause I have found a few, but not many companies that make longtubes for this truck/model, while I was waiting to get them back. Im tryin to sell that Hypertech at the moment and I'm getting it tuned and sensors shut off and all that in the next couple of days. Thanks for the help.

 

I think I'm going to be doing the Y-Pipe setup into a Single Magnaflow but I have one more question. From the Y that I will be making should I run 3 inch all the way to the muffler or would 2.5 be better? I don't wanna go to big but I don't want to restrict it either. Thanks

 

If running a single pipe, go with 3", if duals do 2.5"

 

Thanks man. I was hoping I'd hear from one of you guys. I did a little searching in google and most of the single catback systems are 3 inch, but glad I got a response from someone on here. I'll try to post some pics once I start making progress.

 

i had heard that shortys were a decent upgrade from the manifolds on the old 5.7's...

 

Yea, I believe that they show more gains on the older gen sbc's than they do on the GENIII-IV's...I think that part of it, besides the combustion chamber/valve design, is that the older gen exhaust manifolds were fairly restrictive compared to the newer ones

 

Well I can personally say that I felt a difference in power throughout the entire powerband after installing them. I agree with you both because the factory manifolds on the newer trucks with 5.3's and 4.8's are almost a shorty design. (Each cylinder has its own port). They even look like they would flow better. My factory manifolds don't look like they would flow near as well as those would. Everywhere I read on here says go longtubes and I agree that there is probably more power gains, but I was impressed with what I got out of these shorties.