Merge collectors

[Alan Nyhus]

Originally Posted by Exhausted

A friend told me that this thread was getting some attention so I thought I might put in my 2 cents.

IMO, I have never seen a exhaust port that was smaller than it needed to be.
If you can change say header tube size or step length, or no-step to two step, or collector diameter or length or 421 to 4into1, and not see any difference your motor is not sensitive to what kind of a header it has on it. Another way of saying that is your header is not working to add anything to the way the engine runs, is it?

It is certainly possible that whether you buy headers that come in a box or made for you custom, if the above is the case, it is not simply the fault of the header, ok?

If you do not want to change things in the motor so you can gain the extra power available from the exhaust system, then keep bracket racing and praying you don't have to run heads up with someone who does.

Calvin, a couple of questions. I've got a set of your 4-2-1 headers on my 327/275 stocker motor and want to spend some time on the dyno this winter doing some camshaft work.

- Is backing up the exhaust duration by 4 degrees is a good place to start. Your thoughts?

- If an engine really is over scavenging due to the header design, what are some of the things to look for on the dyno or the track?

Thanks for joining in. -Al