http://www.pro-touring.com/forum/images/icons/icon1.gif Header size?
Im back, I have a question for all. I have a 68 cam that sees mostly street duty but like to get it going to Hits 6 g once in a few moons.
Im not sure on the header size- 1 5/8, 1 3/4, 1 7/8,.
I have a 350 bored 40 = 357
kb hyper piston with about 10-1 comp.
a comp cams roller cam 280hr .525 lift
tfs twisted wedge heads g1
vic jr intake and 750 vac sec holley
th 350 wit h3.55 gears.
electric fan
Over the winter may move to AFRs but thats a big maybe
if not ill polish and clean the TF's
also polish and clean the vic jr. (also have the rpm manifold if engine needs call for it)
and will get a thinner HG to up the compression
Also want to move to a bigger cam such as a 550-570 lift.
Will prob re ring and re bearing the engine also.
So my question is this which may be hard.
I dont know what size headers or brand to get
I have hooker 1 5/8 super comps but they got twisted by a rock so i need new ones.
If i dont do all that work over the winter what is the size i should shoot for as well as if i do the mods planned what size then. Would 1 3/4 be to big either way? Also ive been looking at the hedman headers to and they seem nice and looking to get them with the HTC coating. Any suggs?

One of the largest errors street enthusiasts make is in running too large of a primary pipe, and too large of a collector. For example, NHRA and IHRA Stock teams using Burns' headers in H/SA in traditional small-block powered musclecars are running 1.5-inch diameter primary pipes- much smaller than many street machines are trying to use.
http://www.popularhotrodding.com/tech/0310phr_jack_burns_exhaust_manifold_header_tech/

1-5/8" at the largest, and you want a length in the 40" range and a 2-1/2" collector to get the best secondary scavenging. Here's a discussion on this forum about headers:
http://www.camaros.net/forums/showthread.php?t=16596


You can get the Comp 280HR to .560 lift with 1.6 rocker arms, it works very well with 987 springs.

the 1.6 rockers are a good idea. Ok what is Primary length? Also the hooker super comps have 3 inch collector. Will the exhaust (not headers) still work with a 2.5 collector

Primary length is the length of the primary tubes from the exhaust port to the collector entry. You can get 2-1/2" collectors from several sources, like Chassisworks, S&S, Headers by ED, etc.

Much cheaper to just go with a good set of the Hooker competition series headers. Although the thorley's seem to fit best. If you had no fitment issues I would go that route again only ceramic coated.

The super comps had to be dimpled at the steering arm. Also what is the diff between the hooker comp headers and super comp. i just see the price of hookers with jet hot coating and 600 bucks is a bit of money.

The super comps had to be dimpled at the steering arm. Also what is the diff between the hooker comp headers and super comp. i just see the price of hookers with jet hot coating and 600 bucks is a bit of money.


I think the difference is the thickness/gauge and the super comps have a more equal length to each tube. My 700 hp BBC runs better with the comps.:clonk:I've tried both.


bob

Thorleys 376-1 have the heavier 14 guage tubing and 3/8's flanges and fit very well. I have no reqrets.

so maybe for the street i dont need the super comps. im looking to get the engine to the 450-500 crank power so still nt sure. What about header size. 1 5/8 or 1 3/4

One of the largest errors street enthusiasts make is in running too large of a primary pipe, and too large of a collector. For example, NHRA and IHRA Stock teams using Burns' headers in H/SA in traditional small-block powered musclecars are running 1.5-inch diameter primary pipes- much smaller than many street machines are trying to use.
http://www.popularhotrodding.com/tech/0310phr_jack_burns_exhaust_manifold_header_tech/

1-5/8" at the largest, and you want a length in the 40" range and a 2-1/2" collector to get the best secondary scavenging. Here's a discussion on this forum about headers:
http://www.camaros.net/forums/showthread.php?t=16596


You can get the Comp 280HR to .560 lift with 1.6 rocker arms, it works very well with 987 springs.

If switching from a larger header to a 1-1/2" header will get a H/SA Camaro from 11.61 to 11.41, which one works better? We have a mild 331" SBC that puts 417 hp to the rear wheels through a set of 1-5/8" x 2-1/2" headers.