The Stovebolt Site Forums The Shop Area Engine Shop what size exhaust pipe should I use

I am wrapping up things on my 41 with a 235, I need to do a total exhaust system. What size pipe should I use? Dave

I used 2" from the exh manifold back to the tail pipe when I did the single exh.
I will still use 2" when I change over to duals.
The 216 seems pretty peppy, doesn't miss, stumble or hesitate and starts pretty easy so it seems to be a good size/fit.

Good luck
Dave

I also used 2" for my 235 engine and it is probably overkill. When deciding I think it is important to decide whether you will use mandrel bends or the more typical muffler shop bends that significantly reduce the diameter of the pipe at the bend.

are you making the exh kit? or a shop?
exhaust pipe stock
dual pipes? split headers?

details details
1.5''- is plenty 2.0'' maybe ???

what size is the exh muffler. so size to that and the header. then use a 1.5 exit pipe.

i have a 292, split headers into a single walker muffler and use 2'' pipe.

basic 2 into one

If you are going back stock, the exhaust system is a smaller diameter than 2 inches. I believe it is 1 3/4 or 1 7/8 but I am not positive. I have a NOS muffler and will get some measurements.

Would like to see those dimensions Paul. Are you sure it's a
NOS Chevrolet muffler? Is it still in the box, or stamped with a number???

tks
dg

Here is a pic from my 1942 parts book that gives tail pipe sizes.
LINK

I see in the parts book it does give muffler info.
Group 3.701
1941-49
19-1/2" length of shell, 2" OD inlet, 1-11/16" OD outlet.

Denny, as requested.

[img]http://www.surfacezero.com/g503/data/3176/2014-02-13_11_41_57.jpg[/img]

This is a photo from my image file taken a while ago. I don't have time to take any actual pipe diameter measurements right now as work has me more than occupied for the next couple of days (darn work). Will get the measurements this weekend.

Paul

Thanks Paul, no need for the dimensions, they're in the parts book.
Interesting to see a picture of the real thing and where the
baffle's spot welds were made. Not only is it in the original
box but I see the part number embossed in the shell.
Book says 41-49 Comm, Utility 19 1/2", 2"od exh. flange,
1 11/16 od tail pipe flange.
It's not totally clear when they give the OD of the flanges
whether they are talking about the OD of the flange or the
OD of the pipe that would go into the flange. My guess would
be that it's the later.

What we see as a replacement all to often, are the round
mufflers for tractors sold at the farm stores or FLAPS.
I have often thought about rolling my own from SS. It wouldn't
be to hard to fabricate one that looked exactly like the
original ones, short of the embossed numbers. I'm sure the
baffling inside couldn't be to fancy. I'd love to see an
original one cut apart (Brad)--I know there are bound to be a
few original ones that are rusted thru by now just waiting to
be replace. Was pretty common back in the day to replace the
exhaust system at 30 to 40k. A muffler for the same application
with the same dims was available from Chevy in an aluminized
version, pn. 809750.
Don't understand why they changed the tail pipe size from the
41-49 muffler to the 50-55 muffler. It's a different part
number 3693710, aluminized it was 3794250. Only change in
the two that I can see is the tail pipe flange went from 1
11/16" to 1 51/64". Obviously the later trucks went to a
larger tail pipe diameter for some reason which makes no sense.
Thanks much for the picture.

Denny Graham
Sandwich, IL

As posted above:

1941, 235

Group No.: 3.701
Part Number: 3656598
1940-1949 Commercial, Utility Muffler
http://chevy.oldcarmanualproject.com/parts/1929_54/195.htm

Group No.: 3.701
Part Number: 3693710
http://chevy.oldcarmanualproject.com/1929_57chevyparts/57cmpc0281.htm

I do not know why it changed in 1950, but after seeing Paul's muffler, one noticeable difference (in addition to dimensions posted above) is (I think) that the 1950-56 muffler has the input and output pipe-fittings in the middle of the muffler.

And now you gonna tell us how you know the original 3693710
muffler was centered Tim??? Are you hidin' a stash of them
NOS jobbers in the back room???
The muffler on my '50 had been replace and it's obviously a
replacement, 17 1/2" x 6", the muffler on my '54 is also a
replacement, 21 1/2" x 6", I've got another replacement off
of another truck, it was a '50 3100, 21"x 5".
All these trucks had over 50k on them.
So the only way to tell is as Paul has posted, a NOS, in the
box muffler.

dg

I don't know.

To me, straight through, means straight though (as in 1954, by then the part number and tube diameter had changed)?
http://chevy.oldcarmanualproject.com/shop/1954truck/54ctsm0802.html

As apposed/opposed to a 1941 reverse-flow muffler?
http://chevy.oldcarmanualproject.com/shop/1941/41csm223.htm

The reverse-flow muffler was still used through at least 1949 - then a 1950 "straight-through" construction muffler was used?
http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsm0802.htm

There's no need to be snotty (that should be exercised in the Greasy Spoon, if anywhere)?

Let's look for NOS and documentation.

Ahhhhh yes, Timothy you da man. Never really took notice of
that section, but it clearly shows and describes the
construction of that muffler. The one on my '54 was as I
suspected, and aftermarket exhaust system, the muffler looks
right but the flanges are staggered like the one in Paul's
photo.
The NOS part that Paul has doesn't appear to have rounded ends
as does the muffler in illustration #3 of your second link.
However, in illustration #4 the ends appear flat. Just one
more thing for us to wonder about, probably used an older
drawing for #3 as I seem to remember seeing those domed ends
on some mufflers back in the late 50's when I worked in the
business.
In your last link, to the 1948-51 manual, they carried over the
exact same earlier illustrations.

Thanks for the reminder, i.e., if all else fails,,,,read the instructions.
And you should know me by now Tim, tain't being snooty, not a
snooty bone in me body. I'm just pokin' a bit of fun at ya, I
knew you'd come up with an answer if I rattled you cage, cuz
I know your attention to detail.
Denny G

I have been through those manuals hundreds of time and did not recall there being a photo or descriptions of the mufflers. We lucked out - the illustrations and descriptions seem to be conclusive.

I did not want to refer to the "MUFFLER FACTORY 34-62" that Jim Carter sells. Many people correctly look at JC as being a "gold standard". The "FACTORY" muffler that JC sells is a 1950+ straight-through muffler, but clearly JC has mis-labeled it as being the same from 34-62. It will work for all years, but it is not the design used in all years

Do not worry about the "snotty" comment. Sometimes posters think it is snotty to be asked if they might have documentation regarding statements of originality. A request for documentation is not a challenge; it is an attempt to gather as much documentation as is available.

As we know, Denny, even GM documentation can be wrong or contradictory, but is nice to see documentation if it is available.

Paul's post of a photo of that part/packaging is most useful, and it caused us to think and to search. Thanks, Paul

If I have my back turned to a vehicle and I only hear the sound coming from the exhaust pipe.
I can distinctly tell, that the sound I'm hearing is coming from a 50's Chevrolet Six cylinder truck's straight through muffler.
Its kinda like the old Plymouth car starters, they had a different sound when cranking the engine.

Chevrolet should have trademarked the sound, like Harley Davidson tried to do with there V-Twin engine motorcycle sound.
Ultimately they were denied trademark status on the "potato-potato-potato" sound.
Sound trademark

Never the less there's nothing like the sound of a purring Stovebolt Six.

So true. That sound is even nicer through dual exhausts (even with two original style mufflers). It's not the racket, it's the rhythm and the snaps.

I finally got some time to get some measurements. The critical measurements for the muffler are: inlet 2.00 inches ID, and outlet 1.75 OD. So it looks like the exhaust pipe OD should be 2.00 inches, and the tailpipe ID should be 1.75 inches (I think that would be 1.875 tubing).

For fun, here are some images of a reproduction muffler a military vendor made from my original. He got a manufacture in Canada to reproduce a small run of these mufflers. The repro is attached to the exhaust pipe. I believe he is asking $100 per muffler if you are interested.

[img]http://www.surfacezero.com/g503/data/3285/medium/IMG_62632.JPG[/img]

Here is an image of the reproduction muffler installed. I will need to get the tail pipe made locally as I have never found a suitable reproduction for my application.

[img]http://www.surfacezero.com/g503/data/3285/medium/IMG_62901.JPG[/img]

Paul

Nice reproduction, couldn't tell it from the one in the box,
cept for the finish. Did they use aluminized or galvanized sheet??
Gotta hand it to you guys that tackle that big iron. I don't
have any heavy equipment to handle that big of a restoration.
Fun looking project and thanks for the pixs Paul.

Where bout's in NC are you at, or did I ax you that before???
dg

This guy might have some original measurements of an exhaust tail pipe.
Chevrolet 1 ton panel truck 3800 NOS exhaust pipe 51-55
He has been trying to sell it for awhile.