[NoDOHC]

Actually, it would take less time to leave the center iron side ports open and just cut the outside runners of a turboII manifold, leaving the primary runners only and a single throttle plate at the end. You would have to leave enough of the flange to catch the two studs in the housings and that single bolt in the center plate, but you should have room for that.

It takes a lot of time to fill ports in (although I would DEFINITELY fill the secondary ports, as leaving them will hurt your power a lot). The primary ports will not effect the p-port at all, as the open later and close sooner.

If you set the throttle up so that 50% on the pedal is WOT on the primaries and 0% on the secondaries (peripheral ports) and the 100% is WOT everywhere, I think you will have something. (I actually wanted the primaries to continue past open until they had closed going the other direction - 170 degrees of throttle plate rotation - but either way will work.)

The slider is a very good means of doing this (has been used on transmission kickdowns, mechanical secondaries for carburetors, etc.)

As I said before, this is my idea of a 6PI system that would actually make more power (although it is technically a 4PI).

EDIT: Oh yeah, don't worry about porting the primaries, just clean the manifold up a little. This is not where your engine will be getting the air to make big power, just the air to idle and cruise, which is better if turbulent (smaller port is better).