Not to nit pik, but you should use titles that describe what you are posting about, makes it easier for us to know what's going on.
The plates on the exhaust side actually increase the flow and scavenging by taking that huge dip out of the port's floor. On the intake they help bring up velocity and bring some of that 7500 RPM power potential down to where you can use it. My friend had an 8000 RPM 10 second 351 Cleveland that was faster with the port plates But I think he just ran the exhaust plates on his. The 4V heads are just monsters. Really the 2V Cleveland heads are better aside from their crappy open detonation inducing chambers. That's why the Aussie closed chamber Cleveland 2V heads are so sought after. The are the best of both worlds. Think about it. My bad ass AFR 185's have 2.02 and 1.60 valves and a 4V Cleveland head has 2.19 and 1.75 Huuuuuuuge. Hell the "little" 2V heads have 2.04 by 1.67 valves. Still bigger than my AFRs. And my AFR's are technically a little too big for the 331 I am building. Those giant ports and huge valves equal slow air velocity and sluggish no torque, bad mannered driving until waaay up in the RPM where that air finally gets some velocity. To harness those monsters you either need a ton of RPM or lots and lots more cubic inches of motor to get the air flow up to what those 4Vs want. Otherwise I am afraid you'll be super disappointed with your car's sluggish performance. But huge flowing heads only make power when they're flowing huge amounts of air. A 289 just doesn't move enough air to wake those 4Vs up. But I hope you get the details ironed out and get the ride you really really want because it's really all about the fun factor any way.
I get all my information from the blue book my grandfather gave me that he used when he raced. It's direct from ffford.itsfrom 1968 it breaks down all the ford motors and how there built. It's even got his booklet of all his parts and it's insane to see the prices of back then
