hey guys i am looking for a set of long tube headers for my 94 gt i need 1 3/4 with 3'' collectors. the only set i can find is cooks they are too much $$$$ does anyone out there have a 94 or 95 with 1 3/4 headers any other brand?
hey guys i am looking for a set of long tube headers for my 94 gt i need 1 3/4 with 3'' collectors. the only set i can find is cooks they are too much $$$$ does anyone out there have a 94 or 95 with 1 3/4 headers any other brand?
Those are big headers. For a naturally-aspirated 302 or stroker, the MAC 1-5/8" long tubes with 2.5" collectors are more than big enough. The only time you're gonna need headers as big as the ones you're looking for is if you have a stroker with forced induction or a transplanted naturally-aspirated big block.
Very wrong!
So will these be to big for a 306 with afr 185 heads?
Very wrong!
So the thickness of not even two quarters is going to make or break a hot 306?
It could. That's flawed logic as well. By the same logic, you could say 5° of timing or a few milliseconds of valve timing doesn't matter since those are pretty small values.
Looking for thoughts...
I didn't quote the whole thing because its long, but that was a great post.
This is beyond my knowledge of how airflow works, but air does travel down the sides of the pipe in a swirling motion, so I'm not sure if the volume of the pipe matters so much as the diameter. But how much does the diameter matter? My point being that worrying about 1.625 vs. 1.750 isnt as critical as the other pieces.
I also know that interrupting that swirling flow has major consequences, so that the point of interconnection to the head is important, and the point of merging collection is important.
You want the header to be small enough that velocity of the flow is not slowed to prevent scavenging, but large enough so that the volume of air exiting the head can escape. We don't know if the car is street or strip either...
I like your point about the "normal" 302 header size vs. 347. I think you illustrated well that displacement shouldn't be the determining factor of header size.
Adam
I really like your thought process as well
I wish I had more time to read up on it.
Have you ever read of any of Gordon Blair's stuff?
He has a book called: Design and Simulation of a 4-Stroke Engine.
From my understanding, it goes VERY in-depth on topics such as this, and anything you can think of with an internal combustion engine. I was thinking of purchasing it soon...
I figure understanding just 5% of his stuff would be more than the 100% I have learned elsewhere