390 header

[kartboy63]

what is a good header for a 390 on small tracks, the 990 or a 1.250, I have been looking at the rapp headers just not sure on the size.

 

[alvin l nunley]

what is a good header for a 390 on small tracks, the 990 or a 1.250, I have been looking at the rapp headers just not sure on the size.

I wonder, almost twice the CCs, seems like a larger exhaust pipe would be better. How much bigger are the valves versus the smaller engine?

 

[CarlsonMotorsports]

Already answered this question in your other post.
1.250" is for a highly modified 390 engine (which you said you had.)
The .990" pipe is for the bone stock 390 platform engines. I believe it was originally designed for the mini-cup cars and the likes that must run stock components.

There is a great discussion in your other thread on determining effective lengths of pipes and stages, pretty clearly explained as well.


-----
Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com