Newbie to this site, don't see an Exhaust section but seems this one closest. Healthy '70 442 with headers, 3" exhaust w/ X-pipe & 18" (straight thru) Magnaflows. After years now I really would like to reduce at least 1/2 of the interior drone; not too bad about town, but even on a short drive it's dreary. So I wonder...how about adding a pair (yes,now 4 muffs) of small non-restrictive muffs. Dynamax has the smallest, 4" x 12" (3" openings) straight-thru with baffling between perforated center tube & outside shell. Least restrictive placement would be just inside back bumper, but I think drone originates way before that. So, attach just aft of the collector flange, I'm thinking it won't be measurable restriction as it's a 3" (inside) tube attaching to a 3" exhaust. Seems should work, but I'm concerned that perhaps it's the 3" exhaust size itself that creates the drone, thus I'm stuck with it. Street/strip car, mostly street but most time/attention/$$ concentrates on performance. I've learned past few yrs that exhaust systems are a lesson in physics. Any experts or similar experience out there? Thanxx.

 

Personally I'd just lose the Magnaflows and install Walker Dynomax Super Turbos. There are a number of 3" inlet/outlet versions in different body lengths.

 

Wow Joe, you really like Oldsmobiles!
Not really looking into brands, but science behind sound. I have a survey grid of few dozen mufflers (found on Mustang site, try to post it when get home & find it), comparing Db, HP & Torque levels at idle, cruise & WOT; Borla came in 1st & beat some to death. Magnaflow 2nd for 1/3 the price & only about 2 HP diff. Dynomax good, not fantastic, but beat FMaster badly. Anyway, picked Dynomax as an auxilliary muff due to small "bullet" size & size with straight-thru design should have negligable power loss effect...problem is I don't know if it will make a noticable difference.
Mayby I'll be the 1st & post it for whomever.
Glad I found this site. Formerly with ROP several yrs but had signing on probs year ago & finally got back on, now it won't let me again. I don't think they really have an Administrator &/or does not respond, didn't know any site tried to limit participation. I do like their tech sections & being primarily performance oriented. With the hood down a novice may think my 442 is stock (except for big MT's), but now I prefer concentrate on a little more comfort rather than reaching that elusive 10's. Thus, try get rid of some of that drone & be happy in mid 11's.
Thanks...hopefully some other replies (don't think too many folks thrilled with this section).