[92GTA]

I'm on my 3rd set of mufflers. I've posted a video of my 69 with the Flowmaster 40s, then I made a thread about how disappointed I was with the sound of the Pypes Race Pros.


I just had a set of Flowmaster 10s installed about an hr ago, EARGASM!!!!! The car sounds absolutely freakin amazing! I could never have imagined a better sounding exhaust in my wildest dreams. My car finally sounds like my dream car. I'm so freakin happy I just had to share. My entire life as a car guy I have lusted for a car that sounded this good. I had one the whole time, just not with the right mufflers.


Thanks to everyone here that has helped me along the way and made recommendations. I know sound is a very personal thing and affected by many variables unique to each build.



I'll be posting a video of the 10s in a couple days using the same camera in the same spot that I filmed my 40s video so it will be a good comparison and I'll upload it to my YouTube channel.

[tom s]

This is interestingI run the HP2 Hushpowers.
https://www.youtube.com/watch?v=EUUteVjNdI0

[92GTA]

I Dunno, even after watching that video I'm glad I went with the 10s. They sound deeper/throatier than the HP2s. The HP2s sound too much like many modern cars where the exhaust note from each cylinder is a little blurred together a bit. I like the old school sound of a great cam and a nice deep echo in the exhaust.

[tom s]

10s are worse than 40s and I HATED them!Actually took them off and gave them away!Tom

[72projectbird]

10s and 40s are some of the best sounding mufflers to ever grace this earth.

[92GTA]

Originally Posted by 72projectbird

10s and 40s are some of the best sounding mufflers to ever grace this earth.

^^^This

[tom s]

You guys have a lot more tolerance for noise than I do!Tom

[92GTA]

But it's beautiful noise!

[hobbygto65]

That video is kind of misleading because it's a small block Chevy, totally different sound.

[carcrazy]

What I liked when I was younger and what I like now are very different.

[Scarebird]

I agree with Tom, the HP2's sound good, more like a 70 GTO I heard a few months ago with the original exhaust still.

[hobbygto65]

I have 44s on my 462 Catalina and they sound really nice.

[se428bandit]

The flowmasters I used on my wagon had a horrible drone at cruising speed.

[Interceptor]

I have 10's on my GTO, LOVE them for puttering around town but too loud on the freeway, even with overdrive. Changing to Super Turbos.

[tom s]

Interceptor,I like the HP2s better than the Super turbos I was talked into trying them.Im switching back.The HP2 are a little louder at idle but at 2000 on the freeway I think were quieter.FWIW,Tom

[389]

I like the Dynomax Super Turbo 17749, they fit 2-1/2" exhaust pipe. I think there the only ones that come with the flow directors, they say they are suppose to flow well for what they are. I just drive street machines and I'm just interested in tone..

I never liked Flow Master mufflers but I like there exhaust systems.. They have a real nice set of 3" tail pipes for GM A body cars #15819, that exit right behind the wheels....

I'm sitting here with my ears ringing from 50+ years of loud exhaust systems and construction work...

[Lee]

Chassis dyno testing on the same car. Bottom graph was with FlowMasters, top after replacing them with RacePros.

It SOUNDED better with the FM's, but I'd rather have the 40rwhp gain at 5200rpm.

3 times now I've replaced FlowMasters with modern designs, and found significant power/performance gains.

[Formulajones]

Can you explain that test a little more Lee? From the description it appears that you also increased the front head pipe size to 3 inch when you swapped to the race pro muffler?

I have only one car here left that I have flowmaster mufflers on. I run the Super 40's on my chevelle, don't even think they are made anymore.

Yes they are loud, it does sound good, some drone, but I don't drive the car regularly, I only bring it out when I'm in the mood for noise. The car goes mid 11's at 118 mph with them through a complete 3" system with tails. So they either aren't as bad as portrayed or I'm leaving a bunch of power on the table, lol.

Most of our cars here I prefer things a little quieter though, and at some point I may swap out the 40's for a pair of Dynomax ultra flows, not looking for a performance gain, just may want to tame the noise down a bit.

[Lee]

Originally Posted by Formulajones

Can you explain that test a little more Lee? From the description it appears that you also increased the front head pipe size to 3 inch when you swapped to the race pro muffler?

I have only one car here left that I have flowmaster mufflers on. I run the Super 40's on my chevelle, don't even think they are made anymore.

Yes they are loud, it does sound good, some drone, but I don't drive the car regularly, I only bring it out when I'm in the mood for noise. The car goes mid 11's at 118 mph with them through a complete 3" system with tails. So they either aren't as bad as portrayed or I'm leaving a bunch of power on the table, lol.

Most of our cars here I prefer things a little quieter though, and at some point I may swap out the 40's for a pair of Dynomax ultra flows, not looking for a performance gain, just may want to tame the noise down a bit.

The previous exhaust on that car had reducers necking the pipe to 2.5" going into 2.5" FM's. I replaced the mufflers and headpipes, going 3" through there. Tailpipes remained the same. No other changes at the test. I later retuned the carb and gained more power.

That same car had felt "flat" at upper RPM as well. It had been to the track, and would leave HARD. It would take other cars off the line, but by half track would fall behind, running bottom 13's around 102mph. It wasn't until I put it on the chassis dyno that I suspected the mufflers. I suspect the mufflers had baffles that had rusted/moved with age, even though they still sounded the same.

My '67 Firebird ran a best of 11.38 at around 118.7mph with 3" FM's. I replaced them with Goerlich large case mufflers. Car was MUCH quieter. Back at the track it ran 11.27 at nearly 120mph, no other changes. Sold the car a few weeks later.

On my current low-compression, low-rpm 455 in a '73 T/A-clone project, I previously documented the exhaust changes and performance gains. Although head and tail pipes were changed in it, so not as clear cut on where to assign the gains - although I'm rather confident the gains were mainly in replacing the FM's with Borlas.

[grandam1979]

I had a 3” full exhaust on my t/a with fm 40 and 3” on my grand am with race pros the t/a was much louder and 150-200 hp less. Guys would tell me that they could hear me bumping the gas at the finish line from starting line.