305 header size ???

[Brian Fink]

The Jack Davis headers were 1 1/2 to 1 5/8 to 1 3/4 ;Stahl 1 5/8 were quicker . Jere recommended playing with extensions as opposed to a step design which I did .

[Billy Nees]

Jere wasn't a real fan of stepped headers. He also wasn't a fan of merged collectors. He said, "if your car picks up with a merged collector then your primary tube is too big".

[Ed Wright]

Originally Posted by Billy Nees

Jere wasn't a real fan of stepped headers. He also wasn't a fan of merged collectors. He said, "if your car picks up with a merged collector then your primary tube is too big".

Yep!

[James Jeschke Jr]

1 1/2” x8”Lg. to 1 5/8”Lg. x8” to 1 3/4” is the best I have found.

[Alan Nyhus]

Originally Posted by 71novastocker

What would be the best header size to run. The combo is 175/248. Thanks.

Are you looking for a conventional header or a tri-y?

[71novastocker]

Originally Posted by Alan Nyhus

Are you looking for a conventional header or a tri-y?

Either just looking for ideas. Hoping I pick the correct ones.

[Billy Nees]

Ya know, you don't post with a real name so I can't tell if you're a Newbie or a veteran of Stock. If this is your first build, then good luck picking the "correct ones" the first time around. Heads, intakes, carbs and cams change over time and that will change the working range of this combo. Unless this is a "top shelf, best of everything" build by a known builder, who knows the combo, then I would stay away from a tri-y header to begin with.

[Alan Nyhus]

Originally Posted by 71novastocker

Either just looking for ideas. Hoping I pick the correct ones.

A correctly done tri-y will make more torque and still run up high. It may not show as big a h.p. number on the dyno but may very well go down the track quicker. If you're willing to go further, cam changes can find more power and torque, depending on where you're at now with the cam numbers. Think of the tri-y's as a stepping stone because they are are also a considerable investment. Needless to say, we're talking about a really good set of stainless tri-y's here...something from Cal Elston, Performance Welding or someone that understands exhaust port dynamics, not a set of ebay special tri-y's.

Just my experience with them, FWIW.

For a conventional 4-1 header, I'd happily pick up the phone and order a set of 1 5/8" and go racing:

https://acpheaders.com/

Ben Line is a real craftsman and makes great headers:

https://www.headersbyben.com/

[MEXJOE]

Originally Posted by Alan Nyhus

A correctly done tri-y will make more torque and still run up high. It may not show as big a h.p. number on the dyno but may very well go down the track quicker. If you're willing to go further, cam changes can find more power and torque, depending on where you're at now with the cam numbers. Think of the tri-y's as a stepping stone because they are are also a considerable investment. Needless to say, we're talking about a really good set of stainless tri-y's here...something from Cal Elston, Performance Welding or someone that understands exhaust port dynamics, not a set of ebay special tri-y's.

Just my experience with them, FWIW.

For a conventional 4-1 header, I'd happily pick up the phone and order a set of 1 5/8" and go racing:

https://acpheaders.com/

Ben Line is a real craftsman and makes great headers:

https://www.headersbyben.com/

Ben is very good!