I'm planning on putting new exhaust on my 85 f150 (300 6), and not quite sure how I want to do it. I plan on removing the 2nd cat for sure, but should I remove the first one also? I was thinking of running like 2 1/4 all the way with a cheap muffler. Just wondering if I should take off the first cat too, or leave it on. Also, would you guys recomend I use 2.25 or 2.5 pipe? Thanks for the help guys.

 

with the stock intake I would run the 2.25 pipe ..and put on a nice high flow cat into a dyno max muffler ..as far as I am concerned the muffler is personal preference. new exhaust cat or no cat it sound run alot better!

 

2.5 inch pipe seems to be the normal..... "GUT" the first cat and replace the second cat with a high flow three way cat... go with a Flowmaster or Dynaflow muffler (Instead of the cheap one) and you will love the way it sounds....


go to www.exhaustsoundclips.com to see what some different exhaust systems sound like and to see if you can find the sound you are after......


ftwfred

 

I live in Iowa, no emission laws here, would you guys still leave on the first cat and gut it or just remove it? Would the dynaflow or mufflers still sound ok without a high flow three way cat? I do still have the stock intake. Thanks for the help guys, it's appreciated.

 

The cat ((High flow or not)) will reduce the noise level slightly. I suggest you gut the first cat, remove the second and install a good muffler useing 2.5 inch pipe as far as you can..You need not install a CAT if you do not desire one....

I ran 2.5 inch pipe from the back of the first (Gutted) Cat to the new HIGH FLOW Cat, 2.5 inch pipe from there to a Flowmaster DeltaFlow 40 Series muffler, More 2.5 inch pipe from there to out behind the rear wheel, Right side (Original Location)

Nice and THROATY at the END of the tailpipe, (Where it should be) and not too loud in the cab!!!

Use Stainless Steel pipe if possible so you will not have to do it again soon...Aluminized pipe if stainless is not available...


I remember "Modifying" the filler neck on my new autos so I could get "Leaded" fuel in them...Anyone else do this??
I used to remove Catalytic converters on ANYTHING I owned..
Now I have a Grand-Daughter and I buy Highflow Catalytic converters

My how we change...

ftwfred

 

lol, thanks for the info ftwfred. I think I'll put on an exhaust like the your's, only without the 2nd cat (might add one later, broke right now). Thanks again for the help.

 

ftwfred got his idea from me . i have the first cat in place ungutted with 2.5" pipe running into a flow delta flow 40 and 2.5" str8 out the back. i have a tail pipe on the other side and flex pipe running from the back to make it look like duals (soon to change ). now im gunna remove my muffler to see how it sounds and eventually get a SI (single in)/DO(dual out) flow delta flow 40 muffler to have real dummy (oxymoron?) duals.

PS:v-8 like at idle and the 5.0L sound when its stomped but more raspy and not as deep but its a straight 6 and they have thier own distincitive sound which IMO is awsome

 

Cut both cats. Weld in straight pipe. Reweld EGR tube to keep check light happy. Cut out stock muffler and discard. Weld in muffler of your choice. Cheaper is best. I got a $25 generic turbo-muffler. Keep factor piping if it is in good condition. My stock pipe exits behind rear wheel and looks stock. But runs and sounds better at minimum cost. For the straight six, I wouldn't waste any money on any cat back system. My opinion of course.

Chris