[ramair455ca]

Originally Posted by highrisk

These are a couple of old videos that I did before I started restoring the car but it gives a good comparison between Flowmaster 40s and the Dynomax VTs. The car is a 65 GTO with a 69 428 bored 30 over, E heads ported, Ultradyne 280/288, Edelbrock intake and 800 carb.

Flowmaster 40s https://www.youtube.com/watch?v=xjqr3KNkLqo

Dynomax VTs https://www.youtube.com/watch?v=mT1ee2kQyDw

I really loved the VTs because of how they would quiet down at highway speeds but the clanking at idle drove me crazy. I have since replaced them with Dynomax Ultra Flow SS and these are a very good choice, sorry no video but they are between the VTs and 40s on the highway.

This last video is the engine after I rebuilt it, I had to add it in for anyone interested. It is after we did the break in run and were adjusting the idle and seeing how it responded. Same engine bored 40 over, RaceTec flat top pistons (raised compression to a hair over 10:1), more work to the heads with some milling, nearly zero decked the block (not quit), Edelbrock RPM intake matched to the heads, 1976 Quadrajet (thanks B-Man) rebuilt to match the engine, Lunati VooDoo 60903 cam, Harland Sharp Roller Rockers, Butler Performance Pushrods, 62 SD421 connecting rods, and the lifters are Hy-lift Johnson/Made In The USA lifters from Butler Performance.

https://www.youtube.com/watch?v=UKi96nU0W0o

Dale

Hi Dale,

Because our combinations are similar I'm really interested in whether the current mufflers you have are giving you any drone, and also wanted to ask if you are running headers or cast manifolds? My current set up is 455 powered 65 GTO with a comp cams 242/250 solid lift, 2 1/2" from the RA manifolds to the Goerlich 14" Xcelerators and then out to full 2 1/4" tail pipes. The car sounds OK, but the drone is terrible so I was planning to make the switch to the VT's.

Do you have a clip of how it currently sounds?

[conceptfab]

Here is my 1974 GTO with a 389, 6x heads, summit 2801 cam, 3 tube junk headers, 3" mandrel bent exhaust into flowmaster 40 series and then to 2-1/2" dumps

https://www.youtube.com/watch?v=RujRTr7btJY

Then here is all that with log manifolds, tv7101 turbo, all stainless steel hotside and open 3-1/2" stainless downpipe. This was the first startup and if you listen close you can hear the turbo after the revs

https://www.youtube.com/watch?v=hHLo9URR8BI

[rexs73gto]

I wish I could still get the mufflers that I had on my car in the 80's. They were Marmont turboflow mufflers, they were made for about 5 years & the sweet sound that came from them was music to the ears. They weren't loud but when you got down on it you knew you were in a Pontiac. It made the engine sound just like the old commercials from the 60's of the GTO's that were on TV. But no more Marmont.

[PontGuy]

Here is a before/after video after replacing the logs and 2" exhaust that came on my 74 TA with 2-1/2" RARE manifolds and a 2-1/2" Pypes crossflow system.

https://youtu.be/RWgYDf8R5j0

455+.060 with 5C-4 heads, 72 factory intake, Q-jet, XE268 cam, TH400, 3.08 posi. Not a race car (yet!) but working on it and its coming along.

[djustice]

https://www.youtube.com/watch?v=a7wgFwtqGoQ

update, headers installed, rest of system is the same dual with flowmasters.
throttle response is now near instant, found out that the old log manifolds had 2" compression bendt downpipes. Nigth and day difference, but speedbumps are now almost impossible to negotiate.

[PONTIAC LARRY]

Kind of boring but here was when I put my car back together as pure stock 400 HO with a NOS 068 cam , has repop HO manifolds and full length mandrel bent 2.5" pipes with Jegs brand welded style wanna be flowmasters. I liked the sound. https://www.youtube.com/watch?v=OoNrUCkW8AE

[highrisk]

Sorry, I did not notice you had written me and asked me a question. I currently am running the DynoMax polished stainless steel UltraFlow 2 1/2" straight thru mufflers. I have headers into a 2 1/2" exhaust system all the way back. It has no drone and the sound is great. The mufflers were actually originally set up for a 2 1/4" exhaust system and the input and output was expanded to 2 1/2" at the recommendation of the tech at DynoMax to reduce the drone. The internal pipe is actually 2 1/2" so the flow was not affected. The car has been torn apart for almost 5 years for a restoration so I do not have any sound clips with the current setup.
Thanks,
Dale

Originally Posted by ramair455ca

Hi Dale,

Because our combinations are similar I'm really interested in whether the current mufflers you have are giving you any drone, and also wanted to ask if you are running headers or cast manifolds? My current set up is 455 powered 65 GTO with a comp cams 242/250 solid lift, 2 1/2" from the RA manifolds to the Goerlich 14" Xcelerators and then out to full 2 1/4" tail pipes. The car sounds OK, but the drone is terrible so I was planning to make the switch to the VT's.

Do you have a clip of how it currently sounds?

[post toastie]

68 tempest 40 over 400 with ram air 4 cam and 3 inch hemi style walker superturbos and turndowns at the axle
https://www.youtube.com/watch?v=Tg7G2axXIDo
70 judge with glasspacks and monza tips
https://www.youtube.com/watch?v=Vo-6yR35Pcs