|10-29-2012 12:09 PM|
Big engines are sensitive to restricted exhaust flow. On a Pontiac 455 in a 4x4 Blazer that the dude insisted on using the column shifter, I had to use factory exhaust maniifoolds. It literally KILLED that engine! I bet it loped off a hundred HP and that much torque to boot!
On the same engine I had used 3" Flowmaster 40's w/an H pipe connecting the two sides. Had turndowns about a foot long out the back of the mufflers. They ended right under the rear seat area.
This was in an '81 Camaro. You'd have thought the droning would have been bad- and it probably would have been, had I not used heavy factory-type insulation (tar/felt type) scavenged from junkyard vehicles.
About the best thing that could be said for it was it wasn't very restrictive. But it would set off car alarms just idling through a parking lot- which was something I enjoyed doing where the ricers congregated in the K-Mart parking lot on W. Colonial Dr. in Orlando on weekend nights. Not so enjoyable while driving through residential neighborhoods, like my own.
But it ran great. Effortless 12's w/a 3.08, lower 12's w/a 3.31 rear gear.
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That said, no good reason you can't tune the Edelbrock 750 to work. I don't much care for the non adjustability of the secondary opening rate, unless it's a Thunder series carb.
|10-29-2012 09:26 AM|
Turbo mufflers on a 3 inch sytem behind a big motor like that sound absolutely amazing. I guarantee you will love the sound.
The 750 edelbrock is perfect by the way. Best street carb out there imo.
|10-28-2012 03:58 PM|
|billonwheels||Whats wrong with the Edelbrock? I've had people say Holly, haven't heard of Cliffs.....|
|10-28-2012 03:34 PM|
I went through a pile of mufflers on my Pontiac 455 (462) until I tried the Magna Flow #12640..
If you want better performance, try a Cliffs Quadrajet with a stock Iron Quadrajet intake.. That carb isn't the best for your set up....
|10-25-2012 12:03 AM|
|vinniekq2||noise level will also be affected by power output and cubic inches.Aluminum heads make a different sound than cast iron.ported heads sound different|
|10-24-2012 11:46 PM|
Keep in mind that Flowmaster has 5 different series of mufflers, each with their own sound level. Google it and find out what you want.
1. Super 10 -The loudest of the five, close to open exhaust.
2. Super 40
3. Super 44
4. 50 Series Delta Flow
5. 70 Series - Quietest of all of them with a mild tone
|10-24-2012 10:31 PM|
|billonwheels||Seems like Flowmaster is what everyone's using. I don't have anyone around here with Magna Flow. Any sound diffrence between the 2? These Glass Packs got to go....|
|10-24-2012 09:54 PM|
3" i totally agree. Flowmastwr for me was a quick fix. I was shocked at the quality when i opened the boxes. Sales dude at jegs new what i needed and got me everything including clamps and turndowns in one shipment. He had a monte.
|10-24-2012 09:39 PM|
|vinniekq2||buy a 3 inch system and get the mufflers as far back as possible. I use an X pipe for sound,its a lot quieter than true duals|
|10-24-2012 08:11 PM|
|10-24-2012 07:40 PM|
|billonwheels||Thanks, Still working on it. Pontiac excitement!|
|10-24-2012 07:37 PM|
|10-24-2012 07:24 PM|
Love the car i had almost the same setup. 71 gp sj 455 ho 472. Edelbrock heads built block. Same issue with old exhuast car was flat. Installed flowmaster dual kit with 40 series. It made as much power as open headers. Think i got a kit for a g body and some extender pipes and it was bolt on. Mufflers in front of the rear end.
Glass packs always kill power. They have onthe to cars i tried them on.
|10-24-2012 07:19 PM|
|billonwheels||I'm going with dual exhaust next week so the glass packs are coming off, it was just a quick fix. Magnaflow was on my mind. want a diffrent tone than the typical Flow master.|
|10-24-2012 06:56 PM|
|S10 Racer||Thats a typical problem with the old glasspacks. The back pressure they cause (somewhere around 15-18psi) is robbing power from the motor. A good quality muffler like Magna Flow, Walker Ultra Flow, Thermal, A'PEX, Borla, etc. are good low back pressure mufflers. Any of these will only cause about 1-2psi back pressure. It's not the tuning, it's in your mufflers.|
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