Header size for 430 inch sbc

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Post Reply
gnicholson
Pro
Pro
Posts: 356
Joined: Tue May 06, 2008 9:59 pm
Location: kansas city mo

Header size for 430 inch sbc

Post by gnicholson » Mon Feb 12, 2018 3:02 pm

Im in the process of going back together with this 4.200 by 3.875 11 to one street sbc. It has 1.750 3 inch headers on it now with 3 inch exhaust all the way out the back. Its a 69 vette so the mufflers have to basically be where they are and 3 inch is about as big as i can go. My question is with the exhaust would it be worth going 1.875 by 3.5 headers? My guess is it would help a little over about 5500 rpm and probably not be worth it for a street car. It should make about 600 hp

lekid
Member
Member
Posts: 67
Joined: Thu Oct 28, 2010 3:49 pm

Re: Header size for 430 inch sbc

Post by lekid » Mon Feb 12, 2018 4:13 pm

In my opinion, for torque, 1-3/4" into 3" is probably decent. For horsepower, the 1-7/8" into 3-1/2" will make more for sure!

What vehicle is that engine in?

gnicholson
Pro
Pro
Posts: 356
Joined: Tue May 06, 2008 9:59 pm
Location: kansas city mo

Re: Header size for 430 inch sbc

Post by gnicholson » Mon Feb 12, 2018 4:16 pm

69 corvette tko 600 5 speed overdrive 373 gear

Newold1
Guru
Guru
Posts: 1211
Joined: Fri Apr 08, 2016 9:50 am

Re: Header size for 430 inch sbc

Post by Newold1 » Mon Feb 12, 2018 4:38 pm

I think your finishing thought in your original post answered your own question quite nicely.

As a suggestion based on your transmission type, put the dollars into a nice set of 4:11 rear end gears instead of headers and in street driving you will see more performance in the "butt" dyno and be much happier!

gnicholson
Pro
Pro
Posts: 356
Joined: Tue May 06, 2008 9:59 pm
Location: kansas city mo

Re: Header size for 430 inch sbc

Post by gnicholson » Tue Feb 13, 2018 3:22 pm

Someone with pipe max. What are the ideal exhaust dimensions for this thing?

User avatar
af2
Guru
Guru
Posts: 6201
Joined: Sun Jan 28, 2007 4:42 pm
Location: Grass Valley, CA :Northern Foothills

Re: Header size for 430 inch sbc

Post by af2 » Tue Feb 13, 2018 5:09 pm

Put mufflers on and throw all else out the window unless you have 1.250" headers.
GURU is only a name.
Adam

User avatar
af2
Guru
Guru
Posts: 6201
Joined: Sun Jan 28, 2007 4:42 pm
Location: Grass Valley, CA :Northern Foothills

Re: Header size for 430 inch sbc

Post by af2 » Tue Feb 13, 2018 5:12 pm

gnicholson wrote:
Tue Feb 13, 2018 3:22 pm
Someone with pipe max. What are the ideal exhaust dimensions for this thing?
Buy the program like we did.. Larry spent way too much time for someone to borrow it.
GURU is only a name.
Adam

User avatar
af2
Guru
Guru
Posts: 6201
Joined: Sun Jan 28, 2007 4:42 pm
Location: Grass Valley, CA :Northern Foothills

Re: Header size for 430 inch sbc

Post by af2 » Tue Feb 13, 2018 5:16 pm

And you have not even got close on the amount of info Pipe Max needs to calculate your set up.
GURU is only a name.
Adam

gnicholson
Pro
Pro
Posts: 356
Joined: Tue May 06, 2008 9:59 pm
Location: kansas city mo

Re: Header size for 430 inch sbc

Post by gnicholson » Tue Feb 13, 2018 5:32 pm

Fair enough. I dont know have the program so i dont know exactly what info is needed. I can guess. I have seen other people ask the same question on here . I was just curious what dimentions would be optimal. Ive spent money on here i just havent bought that program yet but i will and ive had it on my mind for awhile to purchase

JoePorting
Guru
Guru
Posts: 2522
Joined: Mon Jun 14, 2010 3:16 pm
Location: Lake Elizabeth, CA

Re: Header size for 430 inch sbc

Post by JoePorting » Wed Feb 14, 2018 10:45 am

Big headers are overrated for performance and a big PITA to install and work around. I'd keep what you have.
Joe Facciano

Post Reply