WeGotMud

Projects & Parts => Garage/Tech => Topic started by: ice87 on September 15, 2012, 05:56:16 AM

Title: hp question
Post by: ice87 on September 15, 2012, 05:56:16 AM
I'm collecting parts to build a 350-400 HP 355 for my k5 and was wondering if a header with a 1.5 primary tube can make that goal or if I need to get a header with 1 5/8 primary tube
Title: Re: hp question
Post by: xjs3667 on September 15, 2012, 06:14:50 AM
well   your going to need a lot more than headers to make that goal  loll     jk
Title: Re: hp question
Post by: ice87 on September 15, 2012, 06:27:56 AM
Well I know that that. Headers are the only thing left that I'm not sure which way to go.
Title: Re: hp question
Post by: marshall on September 15, 2012, 11:35:49 AM
Both are a little small, 1 3/4 I would suggest
Title: Re: hp question
Post by: ice87 on September 15, 2012, 12:48:04 PM
Quote from: marshall on September 15, 2012, 11:35:49 AM
Both are a little small, 1 3/4 I would suggest
what would you suggest?
Title: Re: hp question
Post by: xjs3667 on September 15, 2012, 01:21:01 PM
I would go 1 5/8.....    I envy you if headers is all you got left..... Im just starting on my 355 build   guna be around 450-500hp range :)
Title: Re: hp question
Post by: marshall on September 15, 2012, 04:43:32 PM
Quote from: ice87 on September 15, 2012, 12:48:04 PM
Quote from: marshall on September 15, 2012, 11:35:49 AM
Both are a little small, 1 3/4 I would suggest
what would you suggest?
1 3/4" headers
Title: Re: hp question
Post by: Jthomas on September 16, 2012, 03:11:46 AM
Headers matter a lot. And on a naturally aspirated motor, to achieve max power you need to achieve maximum volumetric efficiency. You do need a nice flowing motor and I'm sure that 1 5/8 - 1 3/4  would be ok for a small block. 

Talk to the proformance department at Chevrolet, they will tell you EXACTLY what it needs

Found this in my chevrolet performance manual.  This is what you need for a balls out small block. 

(http://i1074.photobucket.com/albums/w402/J_Thomas123/B84E16A2-9023-45EC-87E4-CD43B174D21A-93-00000009F0EEE8C9.jpg) (http://i1074.photobucket.com/albums/w402/J_Thomas123/B84E16A2-9023-45EC-87E4-CD43B174D21A-93-00000009F0EEE8C9.jpg)
Title: Re: hp question
Post by: xjs3667 on September 16, 2012, 10:28:05 AM
Quote from: Jthomas on September 16, 2012, 03:11:46 AM
Headers matter a lot. And on a naturally aspirated motor, to achieve max power you need to achieve maximum volumetric efficiency. You do need a nice flowing motor and I'm sure that 1 5/8 - 1 3/4  would be ok for a small block.

Talk to the proformance department at Chevrolet, they will tell you EXACTLY what it needs

Found this in my chevrolet performance manual.  This is what you need for a balls out small block.

(http://i1074.photobucket.com/albums/w402/J_Thomas123/B84E16A2-9023-45EC-87E4-CD43B174D21A-93-00000009F0EEE8C9.jpg) (http://i1074.photobucket.com/albums/w402/J_Thomas123/B84E16A2-9023-45EC-87E4-CD43B174D21A-93-00000009F0EEE8C9.jpg)

I believe this is refering to if you were to run open headers as on a race engine.... correct me if I am wrong




also we do need to know if you are running and exhaust or just gunna run open as it does make a difference
Title: Re: hp question
Post by: Jthomas on September 16, 2012, 01:32:14 PM
I'm not sure what they are calling a "tail pipe" but I'm assuming any exhaust after the header?

If not, well it gives you the length and size if ur going open header. This straight from CHEVEROLET PROFORMANCE.