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New exhaust suggestions for a 1959 Cadillac 390 V8

Started by Rob, February 13, 2007, 01:11:30 PM

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Rob

New exhaust suggestions for a 1959 Cadillac 390 V8

Anyone here have a suggestion on exhaust setup for my 1959 Cadillac? I would like a decent sound and upgraded performance from stock. Everyone says Flowmaster but has anyone here put Flowmaster on a 1959 Cadillac? I would like to bring the 390 V8 to life with a decent edgy rumble. What size pipe should I run? What model of Flowmaster muffler have you used?

David #19063

Rob,

My 68 Fleetwood Brougham had 2 duals and glasspacks (I bought the car this way).  Made a nice loud rumble, but a little too raspy.  And I was told it sounded nice running down the dragstrip too.  

I put glasspacks and 2 1/4 exhaust on my 69 Electra Custom 430-4.  It sounded outright wicked.  Very very loud and would cackle easily anytime you took your foot off the accelerator.  It would also easily set off car alarms if I revved it a little.  (Great fun in parking lots.)  But all in all, way too loud.

I would not go with glasspacks if I were you.

My 69 LeSabre Custom 400 350-4 has Flowmaster 50s (3 chambered) and with 2 1/4 duals (I bought this car this way too.  Too quiet.  I was dissapointed.  Barely any rumble at all, not much different than quiet stock mufflers.

I had a set of Flowmaster 40s and 2 1/4 duals put on my 71 Electra Custom 455-4.  Nice powerful sound, much lest raspy than the glasspacks and deeper sounding.  I could get it to cackle if I revved her up and backed off.   Some interior resonance.  My wife thought it was a little to loud, but way better than the glasspacks.  I thought it was fine.

The next big block car I will get I am going with 2 1/2 duals for better breathing over the 2 1/4.  If the shop has an issue with getting the 2 1/2 over the rear axle, I will have them run 2 1/2 through 2 1/2 mufflers then drop to 2 1/4 tail pipes over the axel.

Anything over 2 1/2 duals in a non-racing low revving car is a waste in my opinion.  3 is overkill for a regular street car.

Also, I will be going with the Flowmaster Delta 40s.  It is my understanding the have a very similar exterior sound to the 40s, but the Deltas will have less interior resonance...which would be good.

A friend had a nice very fast late 60s Firebird with duals a X-crossover and Dynomax mufflers and it sounded very good too.  I may look at those as well one day after the Delta 40s.

A few people do not like the hollow sound Flowmasters have, but most seem to.  I like it.

So, my suggestion is 2 1/2 duals, no crossover needed, 2 1/2 Flowmaster Delta 40s, 2 1/2 tail pipes (or 2 1/4 if thats all they can bend to get over the axle), nice little chrome tips.

Oh yeah, do NOT use resonators, theyll ruin what you are trying to accomplish.

And you can choose either stainless steel or aluminized.

Keep us informed of your decision.

David
PS.  Basically, talk to owners of cars that you like the sound of and find out what they are running.  Of course, compression ratios, cams, tuning, etc. affects the final sound as well.

Robert

David

Thank you for all the useful information! I will keep you posted on what I go with.

Art Woody

Try Smithys mufflers. Oldest hot rod mufflers in the business. All 50s sound, I gaurantee youll love them. Ask any old time hod rodder. We always called them smitties, but spell it Smithys. Ive got them on my 53. Look em up.

Robert

Thanks Art! Would those mufflers be the same as glass packs? I wouldnt mind a sound true to the 50s time period. I like Flowmasters but I worry they may sound too weak and glass packs may be too loud. Something in between would be good.

walt #23510

I have a stock 1955 331cu inch motor and Tig welded Stainless Steel Mandrel bent pipes coupled to stainless Flowmaster 50s.Without a crossover tube,the sound was a little too much for me.(not overly loud,but having a resonance that was irritating at certain RPMs and motor loads)Next I installed two resonators,and it totally tamed the exhaust.(too quiet for you)I get my exhaust tone fixes riding Vintage Harleys but its a whole lot cheaper to buy pipes for yor your 4-wheel ride..walt..tulsa,ok

Art Woody

They have a good throaty sound at the tailpipe. Hardly noticeable from inside the car once you get in high gear. At idle, people outside the car think its souped up, and try to get me to spin the wide whites. I dont want it to sound like some ratty old car, just shows off the Caddys unique sound. To me, flowmasters sound great on a high compression engine with 3 & up pipes and big cam, but just sound sound like a bad muffler job on a stocker.

Robert

Art that sounds like the type of sound I would like to get out of the 59 Cadillac. What size pipe did you go with was it 2 1/2 inch?

Art Woody

2 1/2 is what I used, and I can almost swear the smitties improved performance, but maybe it just sounds like it. I did some more tuning about the same time. I took a 1000 mile round trip and got 18 mpg out of one full tank of fuel used completely on interstate 75 cruising at no more than 70 mph. I would not use anything bigger than 2 1/2 pipes, some engines run smoother with back pressure.

Art Woody

I took a peek under the 53 and my pipes look more like 2 instead of 2 1/2.

Robert

Thanks for your help Art! Thank you all for your input! Everyone here is always a big help and I really appreciate it!