Inliners International Forums General Discussion Engines Exhaust and muffler options

I'm hoping to do the exhaust all by myself with Walker parts.
I have a 1971 Chevy 250ci with stock manifolds mounted in a 1965 C10 frame. Walker makes the correct pipes from the manifold back.
Walker front pipe is #48111 and the rear pipe is #44144. All I need to do is shorten the front pipe about 11" because it's made for the long bed and I have a short bed.

The rear pipe has not yet arrived, so I haven't confirmed the ID of the rear pipe but it looks to be slightly expanded to accept the muffler from the photos I've seen.

The muffler options seem numerous. I don't want a loud sound. A stock looking muffler would be fine. Any recommendations?

Here's the front pipe and it has a tulip end for the manifold. I've read that it eliminates the need for a donut.

What size is the front pipe? 2 inch or is it larger like 2 1/4 ?

It's 2 inch.

Just an F.Y.I., those ribbed exhaust sections are the worst flow you can possibly get.
Not saying it wont work fine for you, just an F.Y.I.

MBHD

Wow, I guess I assumed too much. So if I take my truck to a muffler shop, won't they use a machine to bend pipe the same way? Won't it look the same?

Cost is a factor at this stage because I've never driven the truck with this engine and I am assuming that it will run fine and I'll be satisfied. I've spent lots of time and effort on it, but thankfully, not a lot of cash.

I'd like to get this truck on the road with an exhaust that works, period. If I lose a few horsepower I guess I won't cry about it. I think this whole exhaust system from the manifold back will be just under $150 if I stay with this plan.

I'm a novice. Help me please.

Those ribbed sections are bad for flow, but I doubt that you'll notice it from a seat-of-the-pants perspective. It'd be interesting to see a dyno comparison of mandrel bent vs traditional, but it'd be difficult because the bends would have to be exactly the same, same muffler, etc etc. Most of the mandrel kits will come with higher performance parts.

As far as the muffler goes, go with any listed as "stock replacement" or even the budget ones if you want quiet. We sell and install Walker where I work, pretty decent stuff for replacement parts.

x2 on the bends, they will hurt but not much on a stock 250.
A loooooooooooong glasspack works good on a truck as theres room for it and the length makes it mellow and quiet out the back. Just don't get the style with the louvers sticking into the flow. My other favorite for a good cheap muff is/was the Walker Super Turbo aka Sonic Turbo, same power as glasspacks but quieter, just a little healthier than stock.


I hear ya on the cost, its easy to end up with more in the exhaust system than in the motor itself!

[quote=LugnutzWow, I guess I assumed too much. So if I take my truck to a muffler shop, won't they use a machine to bend pipe the same way? Won't it look the same?

Cost is a factor at this stage because I've never driven the truck with this engine and I am assuming that it will run fine and I'll be satisfied. I've spent lots of time and effort on it, but thankfully, not a lot of cash.

I'd like to get this truck on the road with an exhaust that works, period. If I lose a few horsepower I guess I won't cry about it. I think this whole exhaust system from the manifold back will be just under $150 if I stay with this plan.

I'm a novice. Help me please. [/quote]

A typical muffler shop would use a bender that will crush bend the tubing, it would have smooth bends, but @ the bends the ID will be smaller, hence loosing flow, having ribs in the bends will flow worse because it disturbs the exhaust flow.

A high end muffler/exhaust shop will have a mandrel bending machine.
Or they stock/or will order mandrel bent pieces & weld them together.

Like I said, your piping will work fine for you, it's just not optimal.

The way I think is, if there is a way to improve flow, make more power than stock, better mileage, I always try to do it.

It can be a simple mismatch of the exhaust manifold outlet to your new pipe that bolts to the manifold.
The manifold outlet will be smaller than your new exhaust pipe.
Make it bigger to match your new pipe.
Any lumps/bumps or casting flaws that you can see that could imped exhaust flow, port match it & remove the flaws w/a porting tool.
All these little things, attention to detail will all add up to equal more power, better mileage, etc.

Of course when there is not much funds to improve things, you sort of get stuck with what you can do or get by with.

If you want a little bit of rumble with a muffler.

Get as long of a muffler you can possibly fit, that is a performance muffler, usually the longer = quieter.
Some type of Hemi muffler they are called.

If you just want a totally stock sounding super quiet muffler, & super restrictive, look for some type of OEM replacement, or as suggested a Walker muffler.

These look interesting. http://www.dynomax.com/mufflers/dynomax-vt-mufflers

MBHD

What everyone says about flow makes perfect sense. I now wish I'd visited the local shop where I've had work done before. maybe his prices would be reasonable. I can return the stuff I've bought if the muffler shop is reasonable - say maybe around $200. Otherwise I'll just stay with what I have and wait to see how she drives.

About glasspacks, I'd been told that you lose some HP with those. True or false?

For around $25, you can get a thrush super turbo muffler. Go with either 2 1/4 or 21/2 size, the smaller will be quieter. I don't recommend the 2 inch size, just too small. Whatever the pipe size on these mufflers is the same size on the inside pipes. Another option if you want it dead and I mean dead quiet would Be a walker 21784 or it's lower priced equivalent. This muffler was used on all full size 1960s Chevys and many 1970s pickups. About $52 at summitt racing. The cheap version is 18293 at about $28 at summitt. Both have a 21/2 inlet and a 2 inch outlet the end of your exhaust pipe would have to be expanded to fit. No big deal. If you go super quiet I would spend the extra to get the 21784. If you want to run a bigger tail pipe Then 22329 is the same with a 2 1/4 outlet. Myself I would go with the 2 1/4 thrush turbo. The tailpipe will make it pretty quiet. Jay 6155

In the comparisons Ive done, glasspacks don't give up any power at all vs any other muffler. Then again, if you avoid the louvers, the glasspack is just a straight pipe so they flow quite well.

Downside is they are LOUD.

If you compare power at the same decibel level, glasspacks will indeed lose. I like their sound and rumble at idle, if you can live with the noise. Our v8 truck runs dual long 2" glasspacks, very quiet and good enough as it only makes about 150hp per muffler.

If you go the exhaust shop route go with a bigger 2 1/2 inch exhaust pipe for sure. It won't cost much more than the 2 inch, and more importantly if you want more performance later the pipe size is already correct for a single exhaust system. Let's say a 2 1/2 exhaust pipe to a 22329 muffler and a 2 1/4 tailpipe will give you a nice very quiet system with good flow compared to the pipes in the pictures. Decide later to go for more performance? Just change the muffler. Go with headers or twin cast manifolds? Just merge it into the 2 1/2 exhaust pipe. The cheap version of 22329 is 18274. 22329 was used on 305 Chevy pickups and 2 of them were used on the 350 Olds V8 diesel pickups, not loud at all. Summitt price: 22329 $52.97, 18274 $ 32.59. The muller shop may have a better price for the same part. Jay 6155

Thanks to all for the input. I guess I'll see what the local muffler shop will charge. The front pipe can be returned to the Autozone. The tail pipe was ordered from RockAuto, so I'll need to pay shipping to return it.

Meanwhile, for your entertainment, here's what I currently have. I saved the old rusted exhaust pipe that was on this engine when I pulled it from the donor truck. I have my 1965 C10 backed into the garage. By having it backed in, I have better lighting and more room to work. To avoid filling the garage with exhaust, I pie cut and welded the exhaust so it points forward to vent outside the garage. Looks weird. I tell the neighbor kids it's a rocket launcher.

I know it's a hack job but it keeps the exhaust out of the garage!

Wow! That 2 1/2 pipe will be a nice addition especially if it's pointed in the right direction LOL

I would not recommend the Flowmaster 10 I have on my Camaro. It's too darn loud. Car sounds great but it'll make you deaf.

Not sure what size tubing you are planning on using.

You could use a 292 exhaust manifold that has a 2.5" outlet.

The stock 2" manifold is not even 2" when you measure the outlet.

Example: http://www.ebay.com/itm/New-John-Deere-E...=item5d4e97b432


http://www.ebay.com/itm/250-4-1-292-GM-C...627&vxp=mtr

MBHD

In regards to power and sound when relating to exhaust...

Mufflers - Generally, the quieter the muffler the more restrictive to flow. I'm sure there are some mufflers that are very well designed and have a better flow at a similar decibel level to other quite mufflers, but in general the quieter the more restrictive.

Exhaust pipe size - A smaller pipe will have less flow than a larger pipe (obviously) but it will also have a higher velocity.
Just like how to large of an intake port can have a stalling effect on incoming air, too large of an exhaust can have a similar effect.
Larger pipes doesn't necessarily mean more power, but neither does smaller.
A larger pipe will not become a restriction until very high rpms or very extreme engine modifications.
However, if the pipe is too large you can lose some of the scavenging effects of high velocity exhaust flow at low rpms, meaning the spent exhaust fumes can stall and revert back into the chamber during the intake stroke.
The trick is to have the correct size of exhaust pipe, one that is not restrictive at high rpms but doesn't cause port reversion at low rpms.

End result? Without dyno testing individual exhaust pipe sizes on your engine combination, you really can't say for sure what a 1/4 or 1/2" larger pipe would do to your powerband. Maybe 1/4 will feel great but 1/2 will kill your low RPM torque. If you have a generally unmodified engine, I'd stick with the original size. It was usually engineered that size for a reason. If you have modifications, it's just a guessing game (unless you have a dyno and some time/money) on what size pipe and muffler to use.

Mitch has a very good point about mataining exhaust velocity. Hank has a very good idea using the 292 manifold. If there is any way you could swing buying one I would recommend doing it. If its not possible at this time, I would get the 2 1/2 pipe anyway. The shop may have to weld a short piece of 2 1/4 to go to the manifold that you have.IMHO the 2.5 won't hurt a thing. My 78 integrated head nova has a stock 2 1/4 exhaust pipe all the way to the muffler, the first section is original. In 1979 Chevy came out with an upgraded 2bbl integrated head for trucks. The factory exhaust was split manifold with 2 2 inch pipes leading to a single 2.5 inch pipe then the cat, then a 2 1/2 pipe to the muffler then a 2 inch tail pipe. The exhaust was changed to go after more power. The cam and pistons were the same that you have. Now I wouldn't go to dual 2 1/2 pipes, that would fall on its face. Jay6155

Mine is: Langdon headers to 2-1/2" pipe to 2-1/2" Y to single 2-1/2" pipe to a 2.5"/2.5" muffler and out 2.5" It flows very well and I'm not having any driveability issues with it. I'm also running an offy intake and 390 CFM 4 barrel.

I wouldn't go over that though. The single 2.5" works well. If you want dual go 2" or less.

I visited the muffler shop today. He can't make the tulip end like the Walker pipe has, but that's ok. It'll have the trumpet style end and I'll go with the standard intake gasket and insert (I saved my original insert).
Based on his "quote" his price will actually be CHEAPER than me using the Walker parts. He even had a "recipe card" than told him where all the bends should be. He'll bend the pipes this week and hand me the parts so I can hang them. I'll post an update when I have news.

Cool! What size pipe? Jay 6155?

He can make it with 2" pipe. I think part of that decision is he'll be using a "recipe card" amd will not have the truck in his shop to check fitment. I'm OK with 2" pipe. I'm going for a stock quiet muffler. He had glass packs but they had the louvers inside.

Just watch out for those restrictive inserts.

My 65 Chevy SS Malibu had those alignment inserts.
They were smaller than 2" ID. Restrictive.

Took those out & my SS ran much better.

MBHD

The recipe card doesn't know what size pipe is being used. The problem occurs at the connection to the manifold. A bigger pipe has trouble being squished down to fit the manifold. The solution would be to bend the pipe according to the card,then weld on a smaller end to fit the manifold. This would save money later if you go to headers or Landgons or a 292 manifold. Don't know how much extra this would costl, you have to decide if it is worth it. Jay6155

Picked up my exhaust pipes from the muffler shop today. I think I made the right choice. Total including the muffler was $153.28. That's front pipe, rear pipe, muffler and a hanger.

I installed it all but found that it hangs down too low so I think a little extra bending where it turns under the cab will help it hug closer to the frame.

I'll keep updating as I make progress.

By the way, I have a quick question.
Which end of this insert goes towards the manifold?

Ok, I have to ask.
What's the deal on the alignment inserts?

I don't believe I've ever removed one from a 194-292 series engine.
Doesn't the clamp, donut, and swaged end of exhaust pipe do this?
Curious is all.
Thanks

I'm new to all this. All the parts catalogs show a donut type gasket on the flared end of the pipe where it bolts to the manifold. Also, my muffler man knew exactly what the donut was for and how to use the insert. That's all I know.

Stopped by the muffler shop today and had the front pipe adjusted. I'll spare you the details but basically once I got it home I needed to add length to the vertical section that drops down from the manifold. So the final fitment is excellent but the front pipe has two flared sections. Of course I'd rather have it as all one piece. I will verify the final fitment and then weld the segments of the front pipe. For now, I will be satisfied with a functional exhaust. Once I can legally drive the truck to the muffler shop, I'll have a new front pipe made.

The photos may not show it well, but the pipe is 7/8" below the lower frame rail flange and runs perfectly horizontal to the rail. All the other bends look great. I need to add a few support brackets and I need to study a few reference pics to make final adjustments to the position of the tail piece.

Nice job, it looks good and best part is, you did it!
Now, how does it sound?

Just saw this thread. Wasn't sure why you painted your '71 truck engine GM blue instead of Chevy orange? Mine came factory blue in '78 so I'm just keeping it that color for restoration, but I always liked the orange better (looks less like a Chrysler or Ford). I think Integrated-Jay told me first year for blue inline sixes was '78, and probably last year was '81 after which they went to black.

I tried to match the 230ci engine that was original to this 1965 C10. The original 230ci looks identical to this 250ci and the 230ci was originally blue. I'm not an authority on factory colors but I went with as close a match to the 1965 color as I could.

Weird, I thought they used chevy engine orange going back to the '50s. Maybe it was blue sometime prior to that?

Found an answer to that:

http://www.cs.siena.edu/~lederman/truck/Documents/danroyEngineColors/danroyVCCAcolor.html

I guess they used to use different colors for different engines.

Yup the truck engines were mostly different colors.
IIRC the early 40s-60s gray-blue and blue is not the same as the late-70s GM Corporate Blue

Funny, back in the Model T era most all engines were black.
Then everybody went to dark green of some flavor.
Then came the multicolor era of the 40s-60s.

Then everything went blue for a while (GM, Ford, Mopar, and AMC)

Then it all turned to gray and then back to black like the Model T era again. You cant see the engine in the new ones anyway so I guess it doesn't matter.

I try to keep a chart of all the engine colors I can, the link Lifeguard posted seems accurate AFAIK with the right caveats.

I got so tired of everything being orange that I did my 292 in Diesel Green for the Nova with a truck "292 Hi Torque" decal just for fun. Well, it IS Hi Torque compared to the 194 that came in there!

No dought about the Hi Torgue! Jay6155

We've strayed from the topic of exhaust, so I might as well add this photo of my 1965 C10 factory bell. This is the blue I was trying to match. I bought high temp paint from Eastwood that was supposed to be correct . . . and then you open the can and scratch your head and hope it matches better after it dries.
I am happy with the color.

That looks like "Pontiac" blue to me.

No matter to me. I like the color and this is a daily driver.

I got all the hangers installed today and this exhaust is rock solid. All the pipes lined up with the factory locations which means that my exhaust shop did a good job. It is extremely quiet and the engine seems to like this size pipe.

My '78 bell housing on my Sag 3spd has overspray blue on it too. I guess the clutch and bell housing was assembled with the engine prior to painting on the line. They didn't seem to bother to paint the whole bell housing, just get all the cast iron covered and paint on the bell housing just seems inadvertent.