Muffler question

[DSYenko]

Im sure it's been hashed over in the past but i need to buy a pair of 2.5 mufflers to run on my 400-450 horse 454 that i just installed in my 76 Chevelle.What are some good choices for free flowing mufflers.Some noise if fine as it's kinda my Hot Rod for around town but noise is not a necessity but permitted if it comes with the free flow. Thanks

[Chevy454]

Go with the Dynomax turbos...the guys over at Team Chevelle have the numbers memorized, but I tried a bunch of mufflers on one of my '69s, and those won hands down...plus, there is dyno proof they make more power as well as sounding better...and if you wanna get hi-tech, add an x-pipe...

[MosportGreen66]

I know a guy who has a 1981 Z28. Its a 383/powerglide with a tall rear. His Camaro runs 12.80s all day long. He tested the Flowmaster American Thunder and the Dynomax Mufflers on the track... ready for this... his Camaro ran 2 tenths of second faster with the Dynomax units.

Don't make the same mistake I did... buy Dynomax

[Chevy454]

There's a test somewhere here on the net where some well known Poncho racers tested a slew of exhaust setups on a Pontiac bracket wagon...I can't find the link (yet), but a Dynomax w/x-pipe combo was just a shade behind the open header combo...

EDIT: here's the test...a good read for everyone: exhaust shootout

[DSYenko]

Dynomax it is! Thanks a lot!

[DSYenko]

I have fallen a little farther behind than i expected in getting the engine fired up but am finally ready to order the Dyno Max's.How long are the mufflers you reccomend? They make 14's 16's 17's and 20's.The part number for the 20 incher is the one listed in one of the test you linked to but 20 sounds pretty darn long but maybe thats why they flow so well. Hate to get the big ones if the shorter ones flow as well ,just checking to see what you have .Thanks

[musclcar]

i just installed 3" exhaust and dr. gas X-pipe on my 72 camaro with flowmaster delta force 40 series race mufflers part# 94330419. the exhaust note is awesome and i noticed the engine is more responsive.there is some interior resonance but it's liveable and at WOT the sound is unbelievable.the muffler case is 13" long and 4" thick.

[Rat_Pack]

DSYenko,
I used the Dynomax mufflers on my 76 Laguna and I believe they were the 14" ones #17734 with the 2.5" offset inlets and outlets. Check with your exhaust shop as to which ones fit the underside of your car correctly as far as case length but all dual exhaust 66-77 Chevelles have offset inlets & outlets. Most of the exhaust shops here locally keep the Dynomax mufflers in stock or can have them the next day. I can check with the guy that I sold the car to and have him measure them to make sure they were not the 20" mufflers. One thing I did have to do is install a transmission crossmember from a 73 Chevelle SS, so I could run a true dual system with equal length headpipes, as that was the last year for a true dual exhaust in the GM A-body platform. 1974-77 models all had catalytic converters and the exhaust was split after the converter and the crossmember only has clearance on the passenger side for the pipes. Be sure to run a cross-over pipe to equalize the pressure of both sides of the engine, especially if you are using your original trans crossmember...........RatPack..............

[DSYenko]

I already have the 73 duel exhaust crossmember installed.Im just about ready to fire it up and break it in on a old set of manifolds with short down pipes.Then install my nice manifolds and off to the muffler shop next week. Thanks for the help

[Chevy454]

I've never heard of problems with the 20s...and I'm tellin' ya, they sound sooo goood! Even though I'm stuck with a Flowmaster on our Camaro, I'm not a real fan of the Flowmaster sound...on my L78 Chevelle I had a like new set of Flowmasters and promptly discarded them for the Dynomax big cases, and never looked back...but, different strokes for different folks!