It's going to be my birthday on the 23rd so I'm treating myself and my Caddy (1970 Sedan Deville 472) to a new exhaust. I'm going dual 2.25" or 2.5" hopefully with H-pipe, depending on what the shop says will fit, I can't see under there good enough to know if an H-pipe will fit.

I'm going with Flowmaster as I just like the Flowmaster sound more than Magnaflow. I don't want it to be extremely loud, I just want a good rumble at idle mainly, seeing how loud every single Flowmaster I've ever heard is, I probably want the quietest one they make. I suppose its all a matter of taste but I want your opinion and reasons as to which muffler would be the best.

I see they have big block mufflers as well but I don't know if I need those, also they are extremely large.

I'm not going with headers because they would cost a lot more and they seem to be quite troublesome on these cars. The guy at my exhaust shop said they really won't be necessary unless I'm racing anyway.

I feel like I'm going into this rather blindly, any help or advice you guys can offer is appreciated, I'm sure most or all of you know this engine better than I do. Thanks. :)

Speaking from experience, I'd recommend the Flowmaster 50 series. My Fleetwood had those when I bought it (and still does), and they sound great. They sound really nice, but they're a mellow so they won't sound out of place on a Cadillac. I've just got the mufflers, no cats or resonators - I don't know how those would change the sound if you have them.

im running a single flowmaster 40 on my 68 472 and it sounds great and its not ridiculously loud. i had dual 40's on a small block s10 and everyone always commented on how nice the truck sounded. go to the flowmaster website...they have a bunch of sound clips you can listen to.

Speaking from experience, I'd recommend the Flowmaster 50 series. My Fleetwood had those when I bought it (and still does), and they sound great. They sound really nice, but they're a mellow so they won't sound out of place on a Cadillac. I've just got the mufflers, no cats or resonators - I don't know how those would change the sound if you have them.

Being as my car is a '70 is doesnt have a cat either, and I have been told by others not to get a resonator put on either. My buddy has the 50 Series SUV version on is El Camino with a Hi-po'd 350 and it seems too loud to me (He loves it though) but it does fit his car better. I just dont want a Cadillac to sound that obnoxious. I thought with our cars being big blocks it would sound even louder with the same muffler. Is there much of a drone at any speed, or interior resonance? What I'd really like is a reasonably quiet but rumbly, mellow idle, and then a mellow but loudish roar when I nail it, and anywhere in between it should be much less noticable. Beautiful '76 you have there by the way!

im running a single flowmaster 40 on my 68 472 and it sounds great and its not ridiculously loud. i had dual 40's on a small block s10 and everyone always commented on how nice the truck sounded. go to the flowmaster website...they have a bunch of sound clips you can listen to.

One of my friends just got 40's put on his s10, 4.3 I think, it does sound pretty good. I just didn't want my car to be as loud as or even louder than my other friend with the El Camino. Since 40's are supposed to be louder than the 50 series SUV. Although from what I am hearing from everyone else is that it must depend a lot on the car. You guy are saying they aren't too loud, and I'm betting anyone would think the El Camino was loud, so maybe his engine just brings it out a lot more. I wish this wasn't so subjective :banghead:.

I don't like Flowmasters. They sound great (40 series are fairly loud) but calling them the masters of flow is far from the truth since they're chambered. They should call them Soundmasters. The larger the muffler case the quieter it will be so don't run some 13" case mufflers if you want it quiet. I personally plan to run 4 20" Magnaflows, with resonators, on my 75s exhaust for the best flow and low noise level - then cutouts for when I want it loud.

Being as my car is a '70 is doesnt have a cat either, and I have been told by others not to get a resonator put on either. My buddy has the 50 Series SUV version on is El Camino with a Hi-po'd 350 and it seems too loud to me (He loves it though) but it does fit his car better. I just dont want a Cadillac to sound that obnoxious. I thought with our cars being big blocks it would sound even louder with the same muffler. Is there much of a drone at any speed, or interior resonance? What I'd really like is a reasonably quiet but rumbly, mellow idle, and then a mellow but loudish roar when I nail it, and anywhere in between it should be much less noticable. Beautiful '76 you have there by the way!




There is a fair bit of noise on the inside of the car, but it's not bad. I could drown it out with the factory radio when I first got the car, and you can hear a conversation over it fine. You could probably muffle most of it with dynamat if you really wanted to. It's loud on the outside when the engine is under heavy load, but it's fairly quiet at idle and under light acceleration. It gets louder when your secondaries open up. So far, the only other (legal) exhausts I've been able to hear over mine at full throttle was a Torino GT with glass packs and a few of the more obnoxious fart cans.

My exhaust tips are angled down, which some people say quiets it a little by directing the sound. I don't know for sure about that, but the downturned tips at least look good. I'll check to see which 50 series it's got when I get home from work - I think it's the Deltas, but I'm not positive. The old owner didn't know when I asked, all he told the shop was to put on the Flowmasters they thought sounded best, so hopefully the model is stamped on the outside somewhere.

I got a dual in- dual out straight through Camaro dampener on my 70 Eldorado with no mufflers. Great sound. Pretty loud, but roaring. I think it fits the beast.

If i was you id go with 2.5" piping, and H pipe (X-pipe wont fit), and 2 flows 40 series deltas.. i say this from experience.. ive got a 1970 deville sedan with and h-pipe and 2 delta flow 40 series with headers and i love the sound. its a nice rumble at iddle and nice sound on the highway.. sounds beasty. the deltas are just about as loud as the OG 40s outside but they are alot quieter on the inside. im in love. it sounds like a camaro but with the glyde of a caddy

I couldn't find any sort of markings on the underside of mine, sorry. I was hoping it would be stamped on the bottom somewhere. It's probably either the Delta or SUV 50s.

I couldn't find any sort of markings on the underside of mine, sorry. I was hoping it would be stamped on the bottom somewhere. It's probably either the Delta or SUV 50s.

Thanks for looking anyway, Turns out I'm going to buy a new rad as well, this is turning into an expensive birthday :rolleyes:.

Here's my 70 Eldorado. I made this little film in 2000 when I drove it in Tucson, AZ when I was in Flight School. Notice the class badge on the front license plate...

http://video.tinypic.com/player.php?v=vnpjyf