The real way to determine proper primary and collector size?

MY FYN 79

Frequent Racer
Oct 31, 2003
487
0
0
N/E WI
www.cardomain.com
The more I read on the internet, the more I get confused.

I currently run a pump gas 11.0 to 1 6300ish RPM hydraulic roller 406. The headers on my car are coated Hooker 2242 Super Comps. They have 1 3/4 primary tubes with 3 inch collectors. I dont like the primary tube that goes around the frame and limits my turning radius.

The ratio of coated VS. uncoated parts of the headers is equalizing over time :x , so it puts me in a position to have these recoated before they get scaly.. or research some new headers.

I see alot of people talk about how fast their SBCs run with 1 5/8 primary headers. I always read those posts and wonder... are you running that fast because of the headers... or in spite of them?

Could my motor handle a 3.5 collector? Would a stepped 1 3/4 into 1 7/8 be overkill? Would my motor choke with a stepped 1 5/8 into 1 3/4 header? So many questions.. any input guys? Header recommendations, formulas, dyno experiences, tried and true theories?

Thanks in advance for any input!
 

Goob

Top Fueler
Jun 6, 2003
3,641
0
0
Indianapolis
I'll dig around tomorrow, I used to have a link to a calculator for primary tube size and length.......
 
A

Anonymous

Guest
Here, this will make everything perfectly clear...

Clear as mud maybe. :lol:

http://www.burnsstainless.com/TechArticles/Theory/theory.html

http://www.headerdesign.com/

http://www.ssheaders.com/header.htm

http://www.pontiacstreetperformance.com/psp/exhaust.html

At least keep you busy for a while.
 

MonteMike79

Pro Stocker
Nov 7, 2003
1,428
0
0
Erie, PA
Check out the Hedman 1 3/4 headers they stay inside the frame with lots of clearance around everything, they are part no. 65218 I bought coated ones and am very pleased with them. I was looking at the Hooker's but their stupid outside the frame design turned me off. Why go outside when you can stay in ? If you saw the Hedman's and how much room they have and how good they fit, you would say to yourself, what was Hooker thinking when they decided to run those tubes outside the frame.
 
A

Anonymous

Guest
MonteMike79 said:
Check out the Hedman 1 3/4 headers they stay inside the frame with lots of clearance around everything, they are part no. 65218 I bought coated ones and am very pleased with them. I was looking at the Hooker's but their stupid outside the frame design turned me off. Why go outside when you can stay in ? If you saw the Hedman's and how much room they have and how good they fit, you would say to yourself, what was Hooker thinking when they decided to run those tubes outside the frame.

How is the collector length on those headers? Is it real short or a fairly good length?
 

540Malibu

Pro Stocker
May 22, 2003
1,432
0
0
Shrews., MA
as long as the exhaust gets out of the motor as quickly and efficiently as possible the header details dotn matter.....pretty vague, but it depends 100% on your specific combination
 

Barry 85 SS

Frequent Racer
Aug 8, 2005
662
0
0
Newport News, Va
I'd like to know about primary diameters too. I'm running a 548 bbc and some people say I absolutely need 2 1/4" are bigger primaries. Others say 2" in plenty big. I have the 2" Hooker,2241's and would like to know if it is worth the extra money to get bigger custom made headers.
 

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