If you look at most race Zetec motors they ditch the intake manifold early...for example the Alpha and Lumination throttle bodies and barrel throttle set ups..this has been common practice on DOHC 4 cylinders for some time...our new manifolds will help a lot...FWIW A PLAIN spacer does serve to increase the intake tract length which, on some motors with short runner paths, helps the low end,but once again we have a high revving 4 cyl DOHC,if you never want to go above 3,000rpm it would help,not the 'fan' set up but just a plan spacer,but at 'top end' when the intake has good gas velocity it will do little to enhance performance......rembember 'trumpets' and what they are for....
