Originally Posted By: Turbo-6
I believe the head design of all multi valve engines are very poor, they only work because of the multi valve configuration, the ports are all too low for a decent angle to the back of the valve head.

SNIP





Just curious if you have looked a 4200 head close up..

The valves are canted over toward the ports about 35-40*.

If the port and valve size was so poor then explain why each intake valve contributes ~175 cfm at 0.500" lift at 28" water pressure on a 1mm OS 2006 head..



Last edited by efi-diy; 11/13/14 10:59 PM.

51 GMC 4.2 turbo
Can't solved today's problems using the same technology/thinking that created them