I am about a month away from getting dual exhaust for my '52 239 flathead. It will be the last thing I do before daily driving it on the street this summer.
But I've been tossing ideas around and once I am sure of something, I wonder what it would be like a different way.

What I was going to do was 2 inch true duals with glasspacks behind the cab... just before the bend for the rear axle. I wanted to do this because it would give a nostalgic '50s sound, and being a flathead, I wanted to do something a little retro.

However... my cousin lent my his '94 Chevy Z71 for a few days as he went out of town. He has a 3 inch single exhaust with either a Flowmaster 40 or 50. It sounds great with that Flowmaster rumble. This got me wondering, what about Flowmasters instead of glasspacks on my flathead?

Any opinions would be great. I would have posted in the exhaust forum but most of them just want to anger the world and be as loud as possible... and don't care if it sounds good. I also doubt many would take into consideration the unique difference a flathead has as far as sound and the very low rpms.

Thanks!

 

Nothing sounds like a smitty glasspack on a flathead I have a 37 with dual smitty glasspaks man it sounds great!!!!!!!!
I also have a 54 with a 302 with dual 40 flowmasters sounds great to, but that flatty with smittys has a sound all of it own.
Frank

 

I think a 2" or larger pipe kills the true siamese port sound of a flatty. I like 1 3/4 with Smithys or Cherry Bombs. Some guys go to 1 1/2.
OTOH running 2 1/2 pipes and Cherry Bombs on my C brand 396 wakes up the dead when I nail it or back down hard.

 

Karm

It really comes down to what YOU want to listen to. Downside to glasspacks is they usually get cackly sounding when the glass leaves after a fairly short time. If that's your thing, then go for it. Flowmaster is regarded as the modern performance sound. You will know what you are getting because they sound pretty consistent for a long time.

Genuine flowies also cost four times as much as a glasspacks.

 

I forgot to mention I Have 1 3/4" pipes on the 37 I like the sound to each his own
Frank

 

I like a lot of different sounds... even the stock exhaust sound of my flatty is cool. I've always leaned toward a retro glasspack because nobody I've seen around here, even in cruises, has a 50s sounding flathead.

I guess what I really wanted to know was would it sound drastically different with true duals and glasspacks vs true duals and Flowmasters? I don't want to get it done, start it up, and find out it isn't what I pictured. OR drop the extra $$ for Flowmasters if they aren't the best choice... not to mension I have never heard Flowmasters on a flatty.

Remember, it'll be like a stock but retro rod..if that makes sence... basically I want to let everyone know it is a flathead 8, just by listening to it.

Oh, and I don't know what I was saying 2" pipe.. I meant 1 3/4".... been looking at too many glasspacks with 2" in/out I guess lol.

 

Karm

It will absolutely sound different. Flowmasters have an unmistakeable tone. Although all the normal things like pipe diameter, engine size, cat converters etc effect exhaust sound, I don't thinkit would be difficult to tell the difference. Flowmaster tone is recognizable and unique.

You can dump the glasspacks later with little financial loss if you change your mind.

 

I run dual tube headers with 26" Smithy's and 2" exhaust pipes.

They do get louder with age. Can't say about the Flowmasters.
I agree with the others about pipe size. 2" is almost too much - if doing it over I'd go with 1 3/4. Better performance I've heard, as the slight back pressure scavenges better or something of that sort.

Try the smitty's for a year and if you don't like them change them later. I may try FM's next round.

 

Yea, thats what I think I'll do. I've never heard a flatty with a FM so I had nothing to judge by, but I'm sure on Smithy's now.

Just a little off topic now, something about glasspacks. You guys *might* find it funny.
Back in December my friend's exhaust broke on his '95 Toyota Tercel. We could have welded it up again but being 19 y/o we figured lets be different, and mock the local rice racers. So we got some pipe bent and we installed a glasspack. Nicely hidden, with a small 2 inch stainless rolled edge tip just to be cocky. Low and behold it actually sounds far better than any fart pipes and over time it only got deeper and now actually sounds... dare I say... good... you wouldn't believe how funny it is to see rice racers hear the deep mellow tone, they turn and look for the generic chrome coffee can with 5 inch tip, but instead see nothing...... priceless.

Now, don't think for a minute I am promoting putting glasspacks on 4 bangers instead of rice pipes. I'd rather see neither. My friends and I just like to be different than the local trends.... and mock the local import crowd whenever we get a chance.

 

Red's Headers sells a complete system for '48-'52 F-1's.