Header size ?

Suggestions on header size for a 408W with 205AFR heads and 13.1 compression solid roller cam max rpm 7500 Vic jr intake and 950 carb. 1"7/8 or 2" primary tube headers ?

2" gets my vote

1 7/8"

1 7/8 headers belong on a motor with 10.1 comp ..... not a 13.1 408w in race trim

whitefield wrote:Suggestions on header size for a 408W with 205AFR heads and 13.1 compression  solid roller cam max rpm 7500 Vic jr intake and 950 carb. 1"7/8 or 2" primary tube headers ?

If that engine ever drops below 6,000 RPM use the 1 7/8" primary tubes.  Above 6,800 RPM will be the only place the 2" tube will be better.

NA, the 1 7/8" will probably be faster but the 2" will make more power. With those heads.

Long tube headers I would assume ...with a N/A combo at 7500, guessing 3" or 3 1/2" collector with a min. 3" exhaust or no exhaust, I would use the 1 7/8" ...if you want to spray it use the 2". The heads will flow more but like Randy said 700 RPM is not the majority of the pass when you limit it to 7500.

rmcomprandy wrote:

whitefield wrote:Suggestions on header size for a 408W with 205AFR heads and 13.1 compression  solid roller cam max rpm 7500 Vic jr intake and 950 carb. 1"7/8 or 2" primary tube headers ?

If that engine ever drops below 6,000 RPM use the 1 7/8" primary tubes.  Above 6,800 RPM will be the only place the 2" tube will be better.

5000 stall . I limited it to 7500 rpm due to having a stock 74 block . I thought about turning it on up to 7800 or 8000 RPM. NA engine.

I ordered the 1 7/8 with 3" collector long tube kooks headers . Thanks for all of the replies!

That video is a hoot and a shocker.

maverick wrote:That video is a hoot and a shocker.

& easy hp. lol

cousin had a vega with a decent 406 sbc in it, it had 1-1/2 tubes, ran 11.00, finally got some big hp building tubes for the car , thinking the was lemons maybe, like $1000, 1-3/4 or 7/8 tubes, merge collector , all the tricks..car ran 11.00 after wards, my headers are my car are beat to shit, 1-3/4 it runs 6.60s, maybe ill dent it some more

Oh hell, next someone will say single pattern cams are good.

supervel45 wrote:Oh hell, next someone will say single pattern cams are good.

Everything has its application........ most build with their wallet not their brain.

how bout a stepped header, 1-7/8 into a 2"...?

johndickjr wrote:

I'd rather have a maple syrup enema and sit on an ant hill then deal with David Freiburger on a daily basis!