The whole book is online

John Lingenfelter on Modifying Small-Block Chevy Engines High Performance ... - John Lingenfelter - Google Books





http://books.google.com/books?id=GUC...0chevy&f=false

 

Very good read ! Thanks ....

 

Nice find! Thanks for posting.

 

Interesting read - thanks!

 

I bought his books years ago when he was into prostock truck drag racing

 

RIP John, I remember that 73 Vette Super Stocker running when I went to the drags, thing launched hard! Should have stayed far away from those rice burner POS cars!

 

I read John's book whenever I need a refresher on the parts I have chosen for my street vette. It is always a good reminder about what works and best bang for buck. Good SBC tech from a pro. I keep both his, Vizard's and Smokey's books on my shelf along with a host of others from Motorbooks, SA Design, etc.

 

I found it interesting that they based primary size off horse power in stead of cubic inch. Thanks for sharing.

 

Glad I read that know what to do now. 268 extreme energy comp cam in my L/48. bolt on some 1 7/8 primary, 4 inch collector dia. side pipe headers with three 90 degree bends in the primary tubes instead of the two for under chassis.. It should look good and be loud. How the hell can I get the H-pipe on there ? It could be worse a 78 stock exhaust system lol.

 

Well, power is a function of flow...more flow, more power, more flow = bigger header diameter. A hot 350 making 1.4 HP/CID is going to need a bigger primary than a mild 400.

I still like Vizard's approach of using exhaust flow for primary size.

Waiting for the math post showing how to get a 5k torque peak for a mild 350 with a huge header ;-)

 

Maybe math is a bit too much for some folks so lets simplify this and do it Billa's way.
On this page you will find an article talking about David Vizard's method for finding the appropriate size of a primary by exhaust flow numbers.
http://www.popularhotrodding.com/tec.../photo_03.html

Now lets say we are using the much talked about AFR 195 Eliminator Street SF600 Aluminum heads (a high performance head by any standard but still streetable). We can get the average flow from the exhaust at .600" lift (not hard to come by in a street car) from this page here.
http://users.erols.com/srweiss/tablehdc.htm
That number is 215 CFM for that head.
Now apply this flow of 215CFM to Vizards chart posted above and what size does Vizard recommend.
It appears to be about 1.83 inches for an inside diameter. Wow that's even bigger than using the max torque or max HP number! What do you know????
Even at .500 inches lift If we apply the Vizard chart it comes out to 1.78" inches inside diameter or there about. Most any AFR head using this method is going to net a relatively large primary size it appears.

To see the torque formula see this thread.
http://forums.corvetteforum.com/c3-t...rformance.html

Now factor in the gauge of the pipe in order to get the outside diameter of the pipe needed to achieve this inside diameter. If using a 16 gauge pipe (.0625" thick) then you can get a 1 7/8" pipe with a 1.757 inside diameter or a 2.0" pipe with a 1.882 inside diameter.
There are many ways to skin a cat and maybe one is not much different than another. Maybe the max torque method or max HP method isn't so far off after all, as these would net a smaller primaries as most here advocate vs the vizard chart.

 

No, not at all. It's unfortunate you continue to make my observations personal vs. experience based. I just choose experience, validated by other experience, over math validated by...? and mis-applied to boot; in this case, race engines are very different from street engines in more than just power. And it's not at all unusual to see 2"+ headers on a really hot racing engine. They're spendy and typically impossible to fit in a typical street chassis

Header for a mild street 350 from another thread:

Lingenfelter: 1-5/8
Vizard: 1-5/8
REELAV8R: 1-7/8

Folks can "do the math" on their own

 

Read again. Vizard. Advocated by Billa.

 

 

:grin:


I bet someone could work the numbers to help you come up with a way to bend that 2" H-pipe into a roll bar...and add another 1,000 HP

 

Thank you. I saved this for future reading.

kdf

 

Lol it really does not matter if someone likes the look of side pipes that's what they should do. Its not like anyone buys a C3 thinking it can become a world beater anymore. But a 4 inch diameter collector on a SBC is a little comical. Some truckers spend silly money putting 6", and bigger stacks on there trucks for the look not function.

I'm thinking for some extra chrome look maybe run a pipe from the 4 inch tube over the outside of the body to the other side like one of those 4x4 skellator roll cages. No worry with doors just leave the window down start practicing your dukes of hazard window entry and exit form, be easy with the T-tops off.

 

To be clear I'm not advocating 1 7/8" primaries for a mild SBC engine. What I am advocating is figure out what size you do need if you want to go that route by having some method to do so. Not just taking random suggestions without understanding how it was derived.
Now for the non mathematicians among us (no slight is intended) there are on line calculators available for use. I personally prefer these calculators as it makes it easy to try multiple cams and primary sizes to see what may work best instead of slogging through lots of math.
Knowing how it was derived via the math is just interesting to some people and I know the engineers love it.
Here is one calculator that I found for just primary diameter. As it says, these diameters are inside diameters. So a little math does need to be used to convert that to outside diameter that you need to purchase to get that inside diameter.

http://www.can-of-whoopass.com/index...bmit=Calculate

This is a pretty cool calculator as it also allows you to see at what rpm your current header size will perform best at by inputing the ID and displacement, then getting an rpm spit out.
Or you can put in your peak torque rpm and header size and see what displacement those would be suited to.
Here is a commonly used cam that we can put into this calculator to get a header size.
http://www.compcams.com/Technical/Dy...68H-10_001.asp
It's peak torque occured at 3800 rpm.
Put that into the calculator with 355 CI and you get a pipe ID of 1.56".
Most headers are 18 gauge steel.
18 gauge is .047".
.047 * 2 = .094.

Add this to the 1.56" ID and you get a 1.654"OD.

1 5/8 is 1.625" or 1 3/4 is 1.75".

The 1 5/8 is only .0029"from 1.625, closer to the ideal size.

14 gauge steel however would be .075" * 2 = .15".

1.56 +.15= 1.71" or now a 1 3/4" header.. So know the gauge of steel that the header is made of to get the correct size.
If a 16 gauge steel is used then the number to use would be .0625*2= .125" added to the ID.

This is how to size a header diameter for optimum operation based on peak torque performance for your engine.

If you want to base the header size on some other parameter such as peak off idle performance, then some other method would need to be used.

Hope this helps clear up any confusion.

 

What if you had 4 pipes either 1 3/4 or 1 7/8 with no collector. What would you say the effect would be. Having the right dia, and length collector big effect ? even if you had 1 3/4 primary running into a 4 inch dia. super long collector what's the effect on it.?

 

I run a H-pipe on my exhaust,you can get them from summit for $40 .I have a home made tranny cross member for exhaust room .I use a pipe with a slight bend to fit under the tranny tail shaft .I use some high temp pipe wrap to protect the tranny .