Dyno results of 408 falcon today

This is all to gether another matter. THe pipes BEHIND the collector are VERY IMPORTANT. If you think you are missing something, remove your pipes completly, and if there is any performance gain or loss, you will be able to see it clearly. A good exhaust system will not loose any horsepower at all. I have worked with two very serious race cars, and both will run exactly the same with or without the muffler installed-- WE use Magna Flow mufflers on everyrthing


JOE SHERMAN RACING ENGINES

Joe...

In all due respect, he may be using Fox mustang shorty headers with the tiny diameter ball flange. The outlets on those things are TINY, and EXTREMELY restrictive on an engine like that. Moving up to a header with a standard 3" collector, even a mid-length 1-5/8" unit, would REALLY open things up. I believe Heddman -may- sell such a header that fits.

If you can share what exact headers you have, it would be helpful.

A decent 3" collector with 3" mandrel bent pipe coming off of it will free up SIGNIFICANT horsepower if you are using the crappy Fox type units with the small ball flange.

Good Luck!

Originally Posted by BIGJOE

I have tested headers so many times I can keep count. From one header to another is never a big horsepower deal. On a 1000 HP engine, it MIGHT make 25 HP differance. Think about it. That is two and one half percent-- on 400 HP , that would be 8 to 10 HP. Not worth spending goobs of monet on.. Case in point..552 HP 347 engine, someone talks the guy into custom made headers, bigger pipe with a step from 1 & 3/4 to 1 & 7/8 -- spent 1000 dollars ( after header coating ) the car ran EXACTLY THE SAME, or a tiny bit SLOWER

JOE SHERMAN RACING ENGINES

Joe
What is your opinion on eliminating the "pinch down" at the header flange(SBF) by using the wider bolt pattern found on Canfeild,AFR 205/225,ect heads? Is there power to be gained there?

As a matter of fact, I have done lots of work in this area. On all my own stuff ( dyno or race car headers ) I always spend some time and grind all the extra weld that sticks into the pipe up at the header flange. What I have learned is that all the flow comes right down the center of the exhaust port ( within reason ) the two outsides have very little to do with anything. This can be verified on the flow bench, but it is hard to see.There is very little benefit to doing the full blown cleanup on the header flange. It might be as little as 5 HP, It just makes me feel better about the sloppy welds. It is ALWAYS better if the header flange is bigger than the actual opening on the exhaust port in the head. The most important area is at the top of the port or flange. It is NEVER a good idea to make the head as big as the header flange opening. You can take advantage of the wider bolt spacing if you need to run a much bigger diameter pipe off the head, otherwize, it is no better

JOE SHERMAN RACING ENGINES

Thanks Joe. Really good info!

Sorry jamescomet for the highjack

Originally Posted by 68fastang

Thanks Joe. Really good info!

Sorry jamescomet for the highjack

Don't worry about it, I'm learning a lot from all of this. Thanks.

james comet/falcon