I have a 95 e150 5.8 MAF that I would like to open up a bit. Im looking at a dynomax ultraflow or something similar. Does anyone know how loud such a setup like this would be? Also, what is the pipe size coming out of the second cat?

 

I built a complete new 3" system for my 96 conversion van. The Y pipe retained the original front portion, cut off just forward of the front cat, replaced with dual 2.5" pipe into a Magnaflow fabricated Y connection, that dumps into a single 3" high flow cat. just behind that is a 3"header flange joint with an O2 bung (for the rear O2 sensor in my 96 OBDII) that runs into a Dynomax Super turbo that's 30" long, then into a Magnaflow stainless 3" tailpipe capped with a 3-1/2" chrome tip that ends at the right rear corner of the body. This system is pretty quiet, with just a hint of noise. A shorter 3" turbo would give it more sound.

 

That's an impressive conversion. Im mainly just considering replacing the muffler with a straight piper or straight through style muffler. I might just pull the trigger on it and see what happens.

 

I'd go with a straight through design instead of an straight pipe.

The straight through design with a perforated tube filters only the high frequences, that gives the van a nice dwelling instead of a loud screaming

 

X2. I drove a parts van 80 miles home with a straight pipe. Full conversion interior and it was not enjoyable. 95 GMC with a 350. Sounded good at idle and that was it.

 

That's good to know, and exactly why I think an ultraflo will be right for my application.