jet-tech

I have a 66 convertible with original SB that I've owned for about three years. The exhaust appears to be a stock under car 2" system. The question that I have is, can anyone identify the mufflers installed, p/n 80084971. The 1966 assembly manual shows it should be p/n 3859561-2. I'm not trying to return my car to a perfect restored show winner. I'm just curious whats installed on it now. The exhaust system sounds OK, but after its warmed real good it sounds like it may have a slight rattle sound coming from the muffler itself. Tim

66jack

[QUOTE=jet-tech;1593323623]I have a 66 convertible with original SB that I've owned for about three years. The exhaust appears to be a stock under car 2" system. The question that I have is, can anyone identify the mufflers installed, p/n 80084971. The 1966 assembly manual shows it should be p/n 3859561-2. I'm not trying to return my car to a perfect restored show winner. I'm just curious whats installed on it now. The exhaust system sounds OK, but after its warmed real good it sounds like it may have a slight rattle sound coming from the muffler itself. Tim

I looked in my GM parts book that number IS NOT GM

Your muffler is breaking down internally...time for some new ones...

Jam421

I just logged on to post a similar dilemma.
My '64 has headers to 2.5" exhaust and all I can see on the drivers side is a casting stamp similar to yours " Made In USA" Yours has " 09Y3" beneath those words.
Mine has "0218" with Casting # 8005989. Have you measured the casing ?
Mine was oval 20"L x 10" wide. I've got a new 383 BP engine and I'd like to upgrade the mufflers to higher flow. Going to try the digits in the middle now.
FYI.... I called Ecklers and despite extensive searching they also could not provide a clue!

Jam421

Ecklers advised DynoMax Super Turbos ( #25-10292,3) are back ordered w/no new orders being taken. They could not give me dimensions. I did search thru Google images which had one pic posted. I called this company & waiting for a callback.
This part is 2.5" but I'm sure I saw the 2" as well.
https://www.corvettepartscatalog.com...search=muffler

Search Continues.......

Chambered

I cannot ID the muffler pictured either. The Dynomax Super Turbo mufflers for the C2's are still priced out in the current Walker/Dynomax price sheet, so they should be available. I looked at the stock replacement Walker mufflers & they are obsolete. Dynomax super Turbo #'s: RH = 17764, LH = 17765. They are 14" long bodies, 4-1/4"x9-3/4" ovals, & the 2.5" lead-in pipes appear to be welded on, & the 2" outlet small turns are welded on also. Overall length including all the piping = 26-3/4".

You should be able to order these from any NAPA store, or any place that carries Walker/Dynomax.

Jam421

Okay...finally got thru to Dynomax/Walker and they confirmed there are back orders on these 2.5" mufflers and they are '64 Corvette replacements. Weird as it seems I found 1 each in stock ( 17764/17765) on Amazon.com ! Crazy. They are the Dynomax Super Turbo mufflers 11764,65 at $135 each. I confirmed fitment using the Amazon.com chart + was advised Dynomax is a free shipping return vendor.
So I ordered them . We'll see. Much thanks to Chambered !

Jet-Tech ......Dynomax Walker advised me the above part #'s are for 2.5" inlet but can of course be stepped down to 2" with a reducer . Oddly...although the same company Amazon also lists these part #'s under Walker Super Turbo 17764,5. Yet oddly enough they are priced higher at $160. Dynomax tel# is 1-734-384-7806
These are also available at Summit : https://www.summitracing.com/parts/wlk-17765
Looks like they too still hold a few in stock if you're considering the Dynomax Super Turbo and of course Summit also has a very fair return policy.

jet-tech

Jam421, I just measured the mufflers and are 14' by 9" with 2" inlet. I don't think that these are Dynomax/Walker mufflers. Anyway I will most likely replace these with ones from Allen's. Thanks.

Jam421

Not sure I mentioned I was interested in the Dynomax ST's for a bit more flow but if I can be of any assistance in identifying your castings please let me know.

Ironcross

The Dynamax is a name for Walker exhaust performance mufflers....Its just a universal muffler sold by different size nipples attached to a standard body....Plain and simple. just a fancy Turbo muffler sold in muffler shops and parts stores from coast to coast.....WE SOLD many sets...I even have them on my Vettes and Camaros......