What size header for Alum Block 409 LS1
#1
TECH Fanatic
Thread Starter
iTrader: (1)
Join Date: Nov 2001
Location: Long Island,NY
Posts: 1,015
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech10year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Well I need some help here fellas. I am in the process of getting an Alum block LS1 bored & stroked to 409. I sold the Macs and now I need some new ones. I am looking at 3 sizes, 1 3/4", 1 3/4 stepped to 1 7/8", or 1 7/8 all the way. All of these will go into a 3" ORY into my Corsa. I spoke with some sponsors on what would work best, but I want some opinions on here as well. I was told that the 1 3/4 were to small, the stepped would be awesome, and the 1 7/8 would be a little big and I may give up some low end torque. My car is raced at 3750# so its no lightweight. I am running a 12 bolt with 411, and a TCS 4400 2.7 vertor. I really want the BEST setup possible, I am building this car once so I want to do it right. I may spray the car next year if my S2 tranny from Speed Inc doesnt hold too much longer. They say it will hold to 500 rwhp so any spray would put me over that for now. Is giving up low end torque OK? I may be spinning out of the whole anyway.
What should I do?
Thanks for the help. Bear
![Burnout](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_burnout.gif)
![Icon Confused](https://ls1tech.com/forums/images/smilies2/icon_confused.gif)