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I have a 92 F-350 with a 351 that is lacking power. I think the catalytic converter is clogged. Im planning on taking it out and running a pipe straight through. Is this going to effect the way the motor runs?
Prolly help gas mileage and power a little bit, i cant remember, does the 351 have el torpedo or is it a normal cat, if you want to keep a cat you could get one from catco, theyre like 50 bucks on ebay.
What I did (for inspection purposes) is take the heat shield off the cat and just bolt it around my 3" pipe...hehehe it looks just like the cat is in place.
If you want to get real crazy and want a nice loud truck, take the rest of the system off, cut the cat off just before it flanges up, and weld some glasspacks/cherrybombs or at best, flowmasters, and then some straight pipe... A not-so-quick quickfix though... wont help at all for inspections...
I plan to eventuallyput on dual 2 1/2 exhaust with 22" glasspacks and no cats. until I get the money for that, I would like to take off both cats and replace them with pipe to get more mileage and power but leave the muffler. will this increase the sound any? I'm not worried about increasing the sound (you can tell by the glasspacks) but I don't want it to sound like crap if it does. I might just put on a complete straigh pipe if it wasn't a 6 and I didn't want a ticket. But I'm not going to do that. BTW, we don't have inspection here in OK. They did away with that a couple of years ago. Thanks.
Taking off the cat and leaving the rest of the system will increase the sound big time. ive never heard a truck with the factory exhaust and no cats, but I know when i took mine all off, including the cat, it was obviously really loud. it wont sound great because the factory muffler is just there for its job, to muffle. Once you get the new mufflers on though it should sound great. If you want a pic of my set-up for ideas, let me know.
When I first got my 92 351 both cats were clogged solid. I took them off, fitted a 2.5" pipe and a custom muffler and the truck ran better, sounded great and smelled bad.
I recently moved where vehicles are emissions tested every 2 years, so I put a Catco hi-flo cat on. The truck runs just as good and still sounds great although a bit more civilized now. It also smells a lot better which is more important now that I live in the city with a garage right beside the house instead of a farm where my truck was parked a couple hundred feet away from my bedroom window
IMHO, replace the cat(s) with a single Catco hi-flo. If you can afford to do the whole system, increase the size of the pipe and get a better muffler to boost your performance and improve the sound, rather than taking the cat off or hollowing it out.
I plan to eventually put another muffler on there but I don't have the money for it right now and I just wanted something to give me a little more power and mileage until then. I think I will take one of the cats off and see what a straight sounds like and if I don't like it I can put it back on or replace it with pipe.