Header size for 430 inch sbc

[gnicholson]

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]

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]

69 corvette tko 600 5 speed overdrive 373 gear

[Newold1]

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]

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

[af2]

Put mufflers on and throw all else out the window unless you have 1.250" headers.

[af2]

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.

[af2]

And you have not even got close on the amount of info Pipe Max needs to calculate your set up.

[gnicholson]

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]

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