demented

I have been thinking that the headers I have for my car might be too small for the combination. Here's what the motor is, 622 bbc alky injected, 14 degree heads, two stages of foggers 350hp on the first 250 hp on the second with gas as enrichement, 288 in dur, 306 ex dur. My current headers are 2 3/8 dia. with a 4 1/2 collector, they are a standard style header, nothing fancy. I am thinking I might gain something by going to a 2 1/2" primary and a 5" collector, But I am thinking of a merged collector as well.
Any opinions?
Also are stepped headers something to consider, Maybe a 2 3/8" to 2 1/2" stepped header?

Jardine

How long are they? Primary and collector..

altailites

when I ran my 632 nitrous motor on the dyno it picked up 40 more hp going from 2 1/4 to 2 1/2 on a 500 shot of nitrous if you are going to run that much nitrous I would go with 2 1/2 all the way with a good merge collector . just my 2 -cents

demented

Any body ever use zoomies on a injected alky, nitrous motor?

chevyfireball

I'm running a 632ci with two stages. 400 hp on 1st 300 hp on second. I use 23/8 Hooker Headers with a 12" merge collector 4.5" diam. No probs. As long as your pipes are bigger than your exhaust ports its all good. I think the collector is the most important part, making back pressure etc.

Here's what Hookers say:
By altering the relationship between the primary length and collector diameter and length it is possible to increase or decrease the torque and horsepower output at any specific R.P.M. level. For a slick track the header primaries or Collectors can be shortened to decrease the low end torque for better traction. Larger diameter Collectors will also reduce low end torque. On a good track with lots of bite, extending the primaries or Collectors will pick up bottom end power for a harder launch and awesome e.t.'s. Smaller collector diameters will also increase low end torque.