Exhaust Questions

[bgangsta999]

Okay I just recently bought a 70 shortbed and want to put some exhaust. On my 72 l/b I ran 40 series flows and 2 3/4 pipe in an H pattern out the back. For my 70 I want to run 3 inch pipe w/ 40's out the back. My question is should I run an X pattern or an H????

[kenm78]

I have always liked the X seems kinda easier to me to rout the tubes around trans ect.

[bryanw1968]

The H pipe will help balance the exhaust while the X will balance and scavenge. In a typical street application either is fine. IMHO
In a high HP app I'd go with the X for sure.

[Boise69]

Originally Posted by bryanw1968

The H pipe will help balance the exhaust while the X will balance and scavenge. In a typical street application either is fine. IMHO
In a high HP app I'd go with the X for sure.

Is there a build thread on exhaust somewhere? I'm going through this as well and trying to decide on pipe size and material.

what is the best pipe material to go with?

[piecesparts]

Discussion that I had with Flowmaster, many years ago; hope this will help you.
FIRST: Are you running a Big Block motor? If not, then the 3" exhaust will hurt your performance more than it will help it--Especially if you want to run duals. The size of pipes will hamper the breakdown of exhaust gases and create a reversionary backpressure that will hamper proper exhaust performance. As exhaust gases cool, they create a vacuum effect, which causes the exhaust to assist in pulling the the warm gasses out of the engine. The bigger pipes causes the vacuum effedt to dissapate early and the gases then create a backpressure for the engine to push against. In other words, the smaller pipes 2 1/2" will give a more optimum flow and make more horsepower than the 3" pipes.

Second: The X pattern will scavenge exhaust more efficiently than the H pipe pattern. The H design is a definite torque builder and creates a more balnced flow on a motor than a set of two independent pipes. I would recomend the X pipe design.

[kwmech]

Go with a single 3''. Personally, I got away from duals. Lot cleaner under the truck and a single 3 will be more than enough.

[ProStreet68SB]

Originally Posted by piecesparts

Discussion that I had with Flowmaster, many years ago; hope this will help you.
FIRST: Are you running a Big Block motor? If not, then the 3" exhaust will hurt your performance more than it will help it--Especially if you want to run duals. The size of pipes will hamper the breakdown of exhaust gases and create a reversionary backpressure that will hamper proper exhaust performance. As exhaust gases cool, they create a vacuum effect, which causes the exhaust to assist in pulling the the warm gasses out of the engine. The bigger pipes causes the vacuum effedt to dissapate early and the gases then create a backpressure for the engine to push against. In other words, the smaller pipes 2 1/2" will give a more optimum flow and make more horsepower than the 3" pipes.

I agree with you. Except for one thing. Even if he has a big block, 2 1/2in pipe is the way to go. I'd say unless you have a full blown Strip motor or a street motor that might as well be a strip motor, you should use 2 1/2in pipe, that is if you're going to be doing duals. but thats just my 2 cents

[piecesparts]

I had been looking at 3" exhaust and there is defintiely a breaking point on the pipe size. There are motors that can extract HP out of 3", but you are right, they have to be serious in the build to do it.

[CPNEJR]

i have a 2 1/2 going into a 3 in with flowmasters and no X or H pipe am i losing HP?

[bgangsta999]

I have a 350 with a 3 speed on the tree... So 2 1/2 is the best way to go? What should I expect to pay for this setup. Back home in Cali I payed over $500 for new pipe, 40 series exhaust, and chrome tips... I got a little ripped off IMO. Im in Alabama now and I talked to a muffler guy right outside of the post and he said $400 for my new setup. What yall think?

[LUV2XCLR8]

Originally Posted by Boise69

Is there a build thread on exhaust somewhere?

Ted, everytime something like this comes UP I post this, it is right out of
the Flowmaster Dealers book, it help alot of people out, too small of pipe
can hurt performance, but what alot of people don't know that too big is
an issue also, not enough back pressure can cause issues also, I worked
2.5 yrs. on the side at a local Muffler and Brake shop, X-PIPE is the way
to go IF you have the room, if not a H-pipe will work just as well also

*PS - I have it in High Res also, luv2xclr8@charter.net (Subject 67-72)

[Boise69]

Very neat, thanks for that! so 2.5 is the way to go for my duals. Right now i have neither an X or an H, they are sperates and they run straight back and out the rear. The pipes are not that old, I have a receipt from the PO who had them put in 2004. But they rusted through in 3 different places and the mufflers too, the system is called flowtech. I have their sticker in my window, that will be scraped off soon.

So, are there better pipes to go with or are all pipes made from the same type of steel?

sorry for this Hijack!!

[LUV2XCLR8]

Originally Posted by Boise69

So, are there better pipes to go with or are all pipes made from the same type of steel?

1. Steel (Will rust faster than your gradnma will)

2. Aluminized (Will rust eventually, takes alot longer)

3. Stainless Steel (Will rust after you are buried)

[Boise69]

Originally Posted by LUV2XCLR8

1. Steel (Will rust faster than your gradnma will)

2. Aluminized (Will rust eventually, takes alot longer)

3. Stainless Steel (Will rust after you are buried)

so who sells the whole set-up (with X pipe) in stainless, for our trucks?

Since i'm replacing all of this i'm going to replace the headers too, so far i'm leaning towards the elite headmans

[LUV2XCLR8]

Originally Posted by Boise69

so who sells the whole set-up (with X pipe) in stainless, for our trucks?

Magnaflow Sells a complete kit w/ Mandrel bends for around $600

[Boise69]

Originally Posted by LUV2XCLR8

Magnaflow Sells a complete kit w/ Mandrel bends for around $600

And you feel Magna is the way to go?

I did a poll back in Nov regarding Magna or Flows and Flows won.

As long as you think the quality is there and i can get it all in one place then the 600.00 seems to be a bargain to me.

[Boise69]

Chevrolet C10/20 Cat-Back Exhaust System



Click Image To Enlarge
PRICE: $642.56
PART #: 16643
YEAR: 72-76
DESCRIPTION: Dual Exhaust System
V-8, Dual Exhaust,
Tru-X (rear coil spring), 2.5" SS tubing.
SOUND CLIP: No Sound Clips available
DYNO SHEET: No Dyno Sheets Available
INSTALLATION: Install Sheet
MAGAZINE ARTICLES: No Articles available
CHECK INVENTORY: Check Availability


Thats what i found, does that seem like the right set-up?

[71MUTT]

Eleven years ago I had the local custom exhaust guy redo my whole exhaust sytem with duel stainless. Everything on my truck is slowly rotting away. That exhaust system still looks like new.

Looking at the HP on that chart it shows 350 = 250 HP. I thought that these stock motors were only about 170 HP.

[bgangsta999]

Originally Posted by Boise69

sorry for this Hijack!!

haha no problem man... I knew I wasnt the only one that had some questions!

[Boise69]

Originally Posted by bgangsta999

haha no problem man... I knew I wasnt the only one that had some questions!

I dont know it got out of hand, but my bad. Mine got hijacked too so i guess its questionable topic for many.

what have you decided on doing so far?

[LUV2XCLR8]

Originally Posted by 71MUTT

Looking at the HP on that chart it shows 350 = 250 HP. I
thought that these stock motors were only about 170 HP.

This chart, I think, assumes Headers are in use, and it's not a classic

Ted, I think that's it, I can confirm the part # for ya Thursday, and BTW,
I have flows, Magnaflows that is on "GQ" and I luv them, some don't

[bgangsta999]

Originally Posted by Boise69

I dont know it got out of hand, but my bad. Mine got hijacked too so i guess its questionable topic for many.

what have you decided on doing so far?

This is what I decided... 2 40 flows x pattern 2 1/2 inch pipe, that lead out the back with some nice chrome tips. I had this setup with my last truck and it sounded great!!!!!!!!! Except it was in an H pattern. The HP though wow, let me tell you. It felt so much better after the exhaust. I have on right now duals not sure what kind of mufflers but the pipe is really small, it could use some new exhaust. It still sounds like a truck but just not near how I want it to sound. I need to post some pics of it in a build thread. Most members on here would probably be happy with it how it sits. Im not!!! I.m going for all original for the most part. It could easily be entered into a show.