2.5" exhaust on a stock 5.0 ?

Topic: 2.5" exhaust on a stock 5.0 ? (Read 3782 times) previous topic - next topic

2.5" exhaust on a stock 5.0 ?

April 06, 2014, 11:57:26 PM

Is it safe to put a 2.5" exhaust with 1 5/8" headers on a stock 302 / 5.0 engine (not the HO engine) ? Will this hurt the engine or performance ?

Thanks for any help....

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2.5" exhaust on a stock 5.0 ?

Reply #1 – April 07, 2014, 12:47:59 AM

I knew a guy that was building a stroker 418 for a v-6 mustang. Motor took too long, so he put the 3.8 back and hooked up the dual tubular 3.5" exhaust. he said it drove fine and had a ton more power.

just drop it in. if you find a 2 1/2" stuff cheaper or the same price, run it.

2.5" exhaust on a stock 5.0 ?

Reply #2 – April 07, 2014, 12:58:10 AM

It does seem cheaper to get aftermarket parts "used". Just got a pair of BBK 1515 headers for $51.00 on ebay. They don't recommend those for my engine which is why I was worried. They are 1 5/8" tubes, not 1.5" like the stock mustang headers. I would think it would make it more powerful and give it a nicer sound with bigger pipes.

2.5" exhaust on a stock 5.0 ?

Reply #3 – April 07, 2014, 01:04:06 AM

Even at 1 5/8", your restriction will still be between your heads exhaust valves and the exhaust port. i don't see why you would be worried about it enough to bottle neck it more.

2.5" exhaust on a stock 5.0 ?

Reply #4 – April 07, 2014, 01:27:01 AM

Im just going by what is recommended on coolcats.net. They say no larger than 1.5" headers and 2.25" pipes, but then again, this Magnaflow chart says the stock 302 can have anywhere from a 2" to 2.5" exhaust....

http://www.magnaflow.com/07techtips/faq/question10.asp

2.5" exhaust on a stock 5.0 ?

Reply #5 – April 07, 2014, 01:59:48 AM

Coolcats also says to use 2.5" if its the same price and to not go larger then 1 5/8" in another section.

i think coolcats is a good general write up, but the site was started in 1997. Some information has been updated through the years, other stuff hasn't changed since the general efi practice was to rip it all out and go carbed.

you'll be fine, but you can keep ignoring everyone and making new threads if you want. sooner or later someone might end up agreeing with you. Maybe then youll feel validated. your car, your choice.

2.5" exhaust on a stock 5.0 ?

Reply #6 – April 07, 2014, 02:04:13 AM

Yea I am very indecisive because of all the mixed opinions, and it does seem that coolcats does contradict themselves in their exhaust upgrade article. Just trying to play it safe...don't wanna hurt the engine or any of the car since it's only at 63,800. I want it to live a while..... :)

2.5" exhaust on a stock 5.0 ?

Reply #7 – April 07, 2014, 02:36:45 AM

I've got 190k on my cougar and 250k on the tbird.

I've tried to wear out and blow up the motors on these cars. I've got 50k without an oil change on my tbird, and still runs like a top. you will be fine.

2.5" exhaust on a stock 5.0 ?

Reply #8 – April 07, 2014, 02:44:45 AM

LOL....just had an oil change after 3K. Running full synthetic now

2.5" exhaust on a stock 5.0 ?

Reply #9 – April 07, 2014, 03:18:50 AM

I've put about 50k miles on the bird from march last year to december. it ate enough oil, i doubt any was in there long enough to matter. i think the filter is clogged up. personally, id run a hybrid conventional/synthetic if it were me. there is a reason you don't break an engine in on synthetic, and those oils didn't even exist when your car was built. ford has a nice and cheap synthetic blend ment for older cars.

when i quit trying to blow one up, like when i swap the engine, hopefully soon, i might treat it a bit different.

2.5" exhaust on a stock 5.0 ?

Reply #10 – April 07, 2014, 05:54:55 AM

Coolcats is a decent source of information, but don't take it as gospel. I've found errors, and incomplete info there in the past. Just sayin.

Running an exhaust system that's too large is not optimal for performance, but at 150HP, your not going to notice and your CERTAINLY won't hurt the engine AT ALL, as in, IT'S NOT POSSIBLE.

2.5" exhaust on a stock 5.0 ?

Reply #11 – April 07, 2014, 12:55:25 PM

Gary, I am sorry if I had hyjacked your other thread. I felt it pertained to what you were working on. Coolcats is a great site, but most of what is on there came from this forum. Coolcats has a huge chunk of modifying info all in one convenient place, but our forum is a better place for more in debth info. There is just more knowledge and experience to pull from here. Too big of exhaust will not harm any engine. It could perhaps damper performance, but not at the power levels you are working at. The headers and exhaust system you are looking at will do nothing but gain you power.

2.5" exhaust on a stock 5.0 ?

Reply #12 – April 07, 2014, 01:09:43 PM

You can put 2.5" exhaust on your 5.0....it won't affect anything other than your wallet and the time spent installing it.

The standard 5,0, and even the HO by today's standards biggest drawback is the heads. 51 bucks for BBK 1515's...wish I'd looked on evilbay when I bought mine lol.

If you can swing it, get yourself an HO intake at least, or even better, an Explorer intake, and some GT40 or -40P heads and put on too. An HO cam and an EEC from a Fox 5.0 Mustang will get you into the HO power range...around 220-225 horsepower. The better heads (GT40P and bigger exhaust may bump that by another 10-15 ponies. Sure beats the 150-155 or so from the standard output 5.0

Unfortunately with the pistons you have in your block, you're limited to an HO cam, as they don't have valve reliefs like the HO's pistons do.

My current project is an '89 5.0 HO engine, it's getting P heads, BBK 1515 headers, Cobra intake and explorer TB. I sealed it up yesterday and powerwashed it...today is dis-assembly day, with other little areas to clean up. This one is going into my '87 notch. I've already converted to 5 lug, with the dual piston '99+ Mustang calipers up front (which I highly recommend to anyone doing the 5 lug...SO much better than even the standard SN95 brakes!) and 3.55 8.8 rear with Ranger axles and drums. Good stuff. I did have to replace the rear brake line due to..umm...breaking the stock line, but I would have had to modify it to work with the different rear anyway. Thankfully I saved EVERYTHING from the donor Mustang, except for the VIN. lol

Then there's this burning question of what to with this low mile roller 351w sitting in my shop....hmmm. Thunderbird with a 5.8, anyone? Have to decide on whether to spend the millions of dollars on the efi stuff to keep it "right", or spend a few hundred for a carburetor. I have an intake for it...now I just need an AOD to put behind it and whatnot...

2.5" exhaust on a stock 5.0 ?

Reply #13 – April 09, 2014, 08:43:37 PM

The bigger exhaust is not going to hurt anything....besides the afford mention wallet...

The power gains will be something....10-20HP....who knows....the tiny heads, cam, injectors, SD computer will hold farther back then anything....

What is your long term mod goals....might help us help you....how far do you want to go...

Travis

2.5" exhaust on a stock 5.0 ?

Reply #14 – April 09, 2014, 11:10:39 PM

Really just wanted a bigger exhaust tone and rumble, and also power if possible. I could do the HO upgrade with cheap used parts but id have to have someone do it that knows how.