When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I have had a FM 50 on my truck for about 5 years. I never did like the drone at 40mph. I was watching YouTube and came across a David Vizard video (is that correct spelling?) on exhaust. I think it was this one:
In it he tears up FM mufflers and explains why they hurt hp. He also recommends a muff. he helped design and said that it would add 10 hp over a FM. You see, I watch YouTube vids and it shows me how to spend my $. So I bought one of the DynoMax mufflers and it has been sitting on a garage shelf for 3 years, waiting to be installed. Today I installed it, and sitting in my driveway it sounds pretty much the same as the FM. We'll see when I get the truck on the road. Thoughts?
I drew a red line around the flow directional device the Vizard added.
The Super Turbo was also the winner of one of the shootouts on Engine Masters show.
I’ve always liked the sound of them, but would probably have preferred a longer one for a full-size truck.
Are you running duals or single?
My '07 had a FM 3" SI/2.5" Do system when bought, awful drone at highway cruise. A single 3" ID, 28" Cherry-bomb in front of the FM helped a lot, Later the FM rusted, I replaced with similar but in 100% SS, used a 3" ID Cherry-bomb, same 28" length. Drone was reduced a lot ....but still was there. Then one day in my basement, there were a pair of exhaust weights off a Crown Vic seen laying in my misc box, they were intended to kill drone on CVs and MGMs. I think together they weigh 13-15 pounds, maybe more. Put them together, clamped the weight to the 3" pipe under the cab ... as dead weight. Weights are steel pipes with end caps and filled with concrete. 100% killed drone ... it just purrs now.
My '77 uses just two turbo mufflers, has never droned, I've had the same type on probably half a dozen cars / PUs, maybe more over years since the early '70s. Always pleased.
Looked at such for my '07, but it has a near 30 gallon plastic fuel tank to the left of the driveshaft, so went back with SI/DO SS kit.
Last edited by tbear853; Jan 13, 2026 at 10:16 PM.
Engine Masters has a few good exhaust and muffler shootouts.
Sometimes it surprising just how little difference there is.
I seriously doubt that we could tell the difference 5-10 hp make.
It only took a few months and I dumper the Flowmaster Flow FX mufflers, they were way too loud for me.
I bought a pair of Dynomax Super Turbos and I am much happier with the sound and I couldn't feel any difference in power between the Flow FX and the Super Turbos.
Last edited by Rubiranch; Jan 14, 2026 at 11:16 PM.
I run FM 50's on my short/wide 77. No drone what so ever. It's a different story if you run them out in front of the rear wheel instead of all the way to the bumper.
