what muffler should i use

Big six Farmer

Well-known member
Having had 2 home made exhaust systems rust off my 83 F150, i always swear the next one will be welded up in stainless steel. Just having to fab up something quick before winter, i thought i would play around with some sound management ideas... I had a long section of 4 inch pipe i found at the scrap when i was unloading my junk. I have no idea what it came from, but it is as thick as good heavy exhaust pipe... My 300 six has an EFI Head that has been pocket ported, a mild Elgin Camshaft. Offenhauser Dual port, 390 Holley carb. Dual Exhaust manifolds, with 4 foot 2 inch pipes. I cut the old crap off, and welded this 4 inch pipe on. It goes all the way back to the bumper. I welded a cap on the end, and cut a 2x 3 inch hole a foot or so from the end. I am happy with how loud it really is not, with no muffler. To be honest, i kind of enjoy the Hillbilly pipe for now. I might add a 4 inch resonator i have off a Diesel Truck later, put it inline under the Cab... What i am kind shocked with is, it seems i have picked up some power over my 3 inch muffled system of before. I know this all goes against all rules of street going Exhaust pipe sizing. What i come up with is, the tune of my Engine and that it can breathe some. Also i think the 4 foot 2 inch pipes going into this Sewer pipe help... Exhaust expansion and sound wave management was my play here, also on the quick and cheap... Something to think about, like we need more of that.
 

sdiesel

1K+
VIP
i used a ford system from a 6.9l on my six. very quiet, and i suppose it flows well, and, it bolts in.
the 6.9?.....well, loud does not accurately describe straight 4" no turbo, no muffler. Gave truck to a g.f. she loves the "rumble down under". let her have it i say.

the ford systems generally i dont see big problems with. the 351 single into dual i like quite well. it could be nicely modified to fit with the efi six exhaust.
 

MechRick

1K+
VIP
A single 3" Super Turbo or two 2" Super Turbos would flow enough and be quiet. With duals a crossover quiets things down a bit.
 

arse_sidewards

Famous Member
Mufflers last like 5yr at the most in the salt. I just run whatever oval case turbo style muffler I can get with a 2.25+ inlet/outlet in line with whatever barrel case OEM style muffler I can get cheapest with a 2.25+ inlet/outlet. The end result is quet and doesn't rob enough power for me to care.
 

F-250 Restorer

Famous Member
I've been using a FM 50 for more than a year. I'm very happy with the subtle low sound. I get an odd buzz sound for a second when I let off the gas to shift. At first it sort of bothered me, but now I like it. I'm sure it is the pipes and not the FM.
 

Wesman07

Famous Member
Supporter 2020
Has anyone tried the Flow Master HP2? It is advertised to give a old school hot rod sound. It might be a great combination.
 
Last edited:

FordBoy300

Active member
When I first rebuilt my 300 I used the exhaust I already had which was a flowmaster 40 series single in dual out and then after a year or two I wanted to quiet it down a bit and I went with a dual in single out magnaflow muffler.

Both are great choices I love them both.

Hedman header Flowmaster 40 series with exhaust cutout

Efi manifolds Magnaflow muffler dumped before the rear axle

Personally I would like to go back to the flowmaster it just had this awesome sound when you let her rip!
 

DirtbagDan

New member
Don't think I've seen Borla mentioned.. Love their sound!! Quiet when your off the throttle but sound good when you step on the gas. Also everyone runs FM so it's nice to have something a little different.

I've got a headman header with a set the PRO XS mufflers in a true duel setup with 2.25" pipes.. dumped under bed right before the axle.
Only kind of non-issue I have a a vibration around 1200 rpm under heavy load rattles the windows and cab....but like I said it's only for a short duration coming through 1200rpm
 

clintonvillian

Famous Member
Don't think I've seen Borla mentioned.. Love their sound!! Quiet when your off the throttle but sound good when you step on the gas. Also everyone runs FM so it's nice to have something a little different.

I've got a headman header with a set the PRO XS mufflers in a true duel setup with 2.25" pipes.. dumped under bed right before the axle.
Only kind of non-issue I have a a vibration around 1200 rpm under heavy load rattles the windows and cab....but like I said it's only for a short duration coming through 1200rpm
I bought borla proxs 2 in single out, any clips of what yours sounds like?
 

BigBlue94

Famous Member
Supporter 2021
Supporter 2019
I run a short oval cased Borla XR1 on my 300. Clifford headers, 2.5" collector extensions into a flowmaster scavenger y-collector, 3, short magnaflow spun metallicat, muffler and 3" tailpipe. Its very loud. There is a clip in a recent thread of the sound.

I have the Pro Xs oval case on my 08 5.4L. Its not as loud, but still healthy. Factory exhaust upstream from muffler.

I have the FM 50 DF on my 351w. Mellow idle but loud at WOT. No cats.
 

DirtbagDan

New member
I bought borla proxs 2 in single out, any clips of what yours sounds like?
Sorry it took a minute but here is a link to my video.. It's from inside the truck with the sliding rear window open and the driver side window half way down. These are (x2) single in single out 2.5" Borla Pro XS mufflers welded to 2.25" pipe dumped right in front of rear axle attached to headman longtube header

 
Last edited:

Big six Farmer

Well-known member
The quietest free flowing muffler ?.. I know different companys make large high flow performance type mufflers for Motorhomes. they have a large round body and can be 3 feet long.
 

BigBlue94

Famous Member
Supporter 2021
Supporter 2019
Borla 400500 is a "quiet" straight through muffler. Its not Cadillac quiet, but is not aggressive until WOT. Its not cheap, its a stainless borla afterall!

My ProXs fell off and I ran over it with a superduty on my rough cobble driveway. Beat it back to fitting shape and it doesnt even leak. They are tough.
 
Top