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I have Flow Master 50 series mufflers and I really like them, except. They are rather loud on the highway and I'm trying to get a quiter ride. I have headers into 2 1/2" exhaust with cross over and ending under the bumpers. They don't really drone, just too loud for the stereo.
I could A: change the mufflers to ???. B" add a resonator in front or behind the muffler.
thoughts?
1977 F100, short/wide, 400 with a lot of mods.
Last edited by beartracks; Feb 23, 2026 at 09:50 AM.
From what I've seen the closer the muffler can be to the end of the pipe the better it works. You could probably just add a couple of straight through glass pack mufflers in the back and quiet it down a bunch with no loss of performance.
My '07 had a FM on it when bought, and it had lots of drone, but a 28" long 3" ID cherry bomb in front of it helped, but the real "drone killer" was about 10-12 pond weight clamped to the head pipe about midway cured the drone. I just used two Crown Vic exhaust weights welded to a angle iron bracket and clamped in place.
I just wrapped my SS pipe with a sheet of SS to keep from staining the pipe if the U-bolts tarnish.
My '77 had two glass packs the day I bought it in 1986, I parked it for a few days and then my muffler guy got me in, bent new twin exhaust, two Super Turbo Mufflers ever since. No drone at all. Guess if ever needed again will buy a preformed kit as he had to retire due to health.
Last edited by tbear853; Feb 23, 2026 at 11:48 AM.
From what I've seen the closer the muffler can be to the end of the pipe the better it works. You could probably just add a couple of straight through glass pack mufflers in the back and quiet it down a bunch with no loss of performance.
I did this on a previous rig, it toned down the two chamber flowmasters ALOT.
I'm still a fan of the old school glass packs, just put one on my 00 Excursion 5.4, the po had a FM on it and it was absolutely terrible noise and drone, put an 18" gp on it, love it, had the guys at Sierra Auto giving me a hard time about being old when I took it to them to do the swap to 5.13's/Tru-trac, but... they did like the sound
My 77 F150 4x has just a short resonator from an 05 F150 and I've gotten lots of compliments on his sound, at idle it's got a nice tone, and a quick braaap it has a nice bark and cackle down.
Exhaust sounds are very subjective to each person, only newer car I've heard was neighbors '15 5.0 stang and I liked it, nice bark when on it, but normal driving it's not harsh, when I drove it it was pleasant inside with windows up, it was a manual, so it was fun AF to drive I'd like to replicate the sound of it on one of my fleet.
flowmasters have the worst sound on the market as far as I'm concerned. if VW made an air cooled V8 that's what it would sound like.
I have two 48" glass packs midway between the headers and the end of the pipes behind the rear wheels on my 428. I like the sound, and I get a lot of compliments on the mellow but noticeable exhaust note.
I was never a Flowmaster fan untill I got these 50 series. They're not harsh and tractorish at all. I used to run glass packs but the were really loud and kept vibrating the screws out of my interior trim. I think I'll try to squeeze in some resonators.
The Crown Vic exhaust weights are interesting. I think Ford puts a slab behind the seat on some trucks to reduce resonance.
That picture was after I had replaced the terrible loud droning (uncomfortable drone and plain embarrassing) exhaust that came on it which was a 3"SI / 2-1/2" DO style FM aluminized steel system started to leak (rust joints in places), replaced with a total SS "Legato" branded system, same design, and the SS muffler was exactly like the FM, even had polished tips, etc. Was a little cheaper $$. It sounded exact same except no leaks, and since a regular GP had worked some before, I bought the SS version 28" long 3" ID and put it in same place, same mild improvement but still bad at a steady cruise at 1900 rpm. I had those left over weights from a CV system which I had bought off a wrecked '01 CV to put under our '01 MGM (just to upgrade single to dual, was in 2001 not long after purchase, I worked the wreck, elderly couple got hit by a college student at high speed on I-81, spun and hit the guard rail all 4 corners, stopped with hood under a guard rail so when I heard car was totaled, I asked the wrecker buddy where it went since he towed it after the adjuster, was a local yard, $100 got me the system plus 4 new like tires and the lacy spoke wheels and the FS spare), but it too had the weights. So those two were in my scrap box. Weights are steel pipe filled and sealed with concrete. They 100% killed drone.
The last time I had the exhaust replaced on my 1979 F-250 4wd with fenderwell hedders, I had a good friend do it the managaed an exhaust shop.
He asked my if I wanted turbos again and I said, "nope, lets go with glass packs this time".
He said seriously? Or are you just kidding?
When I started it up he was shocked at how good it sounded, he said no one had bought them in a long time.
I'm starting to regret not putting them on my '76.
I have 50 series Flowmasters on my 76 F150 390 with stock style manifolds. They sound really good imo. I want to do headers. The PO took them off because he thought it was too loud.
my 77 f150 351m has magnaflow turbo mufflers. They are quiet but still sound pretty decent. I just bought a Jones Exhaust muffler off Summit, they got good reviews and I wanted to try something different so I will give it a shot. Keep y'all posted when I install.
My vote is try a glass pack where ever it might fit. Behind the muffler if possible.
If you want to try something else I suggest magna flow. Here is a couple videos (I know they aren't the best comparison)
Old smaller 3" in 3" out magna flow
About a year ago I decided to improve my exhaust a bit. I added a big magnaflow, it has a 3-1/2" single exit piped to the side behind the rear tires. The inlet is a dual 2-1/2" plumbed to stock 460 with truck manifolds. It is nice and quiet but sounds good to me. Plus I feel it has more power throughout the range. It had a drone under load at about 1800 rpm cruise in top gear. I watched a video by david vizard about helmholtz resonators and did the measurements and calculations to build one on my setup. I either have the calculations wrong or need to tune the length because I still have the drone but it is noticeably quieter. Interestingly what sold me on this resonator idea is they are putting them on trucks with the new 7.3 gas engine. The idea is you find the resonance (drone) frequency, I used a free phone app. Then calculate the length equivalent to half that wavelength and it cancels it out. The problem is it is dependent on temperature and other things.
Last edited by orangeford; Apr 30, 2026 at 02:27 PM.
Which super turbos did you go with, the offset inlet/ center outlet?
Sorry Kubota,I just now saw this.
The Flo FX were horribly loud (remember I am old) under acceleration, I really can't remember at a cruise but I am sure they were louder than I liked.
They were offset so the tail pipes coulb be mounter highere than the inlet.
They were mounted verticle rather than horizontal.
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I'd like to replicate the sound of it on one of my fleet.
