Piping a 4.2 with no muffler....?

[GqSnow]

I want to pipe my new(to me) '97 f-150 shortbox 4x4 with a 4.2 v6. I've read all the comments you guys have written about duals, thanks by the way, but I'm not a big fan of mufflers after the cat. On my last truck, I just had the guy "y"-it right after the cat, it was on a '90 f-150 with a 302, it sounded mint. I'm wonering if no muffler or performance muffler on a 4.2, piped right after the cat would sound ok, and if it's even legal. I would appreciate any help, thanks.

Ryan
'97 F-150

[ryanstruck]

No, it's not legal. It will probably be too loud to pass inspection, number one, and number two, a stock muffler actually does trap a small percentage of exhaust particles after the cat and block them from being released. If you want to see proof of this, if you have your old one taken off the 97, cut it open and have a look inside...it's pretty ugly, and there's usually a thin film of, for lack of a better word, slag built up. I recommend a muffler like the Gibson (see my previous posting for a link to the webpage and a sound clip of a 4.2L with dual sport and single sport exhaust. If not, use Cherrybomb Vortex Performance muffler (i had this one and it was awesome) or even go with Cherrybomb glasspacks.

1986 F-250 HD 4x4
4.10 gears, C6 trany
351W, Edelbrock 351 Performer intake
Edelbrock Performer 600cfm 4bbl carb
Edelbrock Pro-Flo air cleaner
Extreme 4x4 camshaft
Flowmaster 30 series dual exhaust
Custom headers
3" Warn body lift

[ryanstruck]

[hd1]

I have a 97 F150 with a 4.2L and I had a local muffler shop delete the muffler and install duals out the back.It sounds decent but it seems that every since I did it I have a cold-run problem , every morning I start it up ,leave the drive and about third gear it backfires out the intake. I've had it to the garage several times and have talked to several Ford techs and none of them seem to know if it's related to the exhaust.