In regard to center-oiler block mods, I did an FE engine series for Mustang Illustrated Magazine some years ago. All the machine work was done in the Roush Prototype shop.
I started out with the thought that we've learned a bunch since the basic lines for the FE engine were laid down and it would be of benefit to 'drag the FE engine into the 21st century.'
Jack Roush had many fingers into the various performance offices at Ford and made offers to many of the original engineers. So a number of them started a second career working for Roush. I had access to them as a sort of 'brain trust' and sought suggestions from them.
We did such things as taking a center-oiler block and cutting it up to see how much space we had between oil galleries and water jackets, for instance.
The result of all the eyeballing and head scratching was that we opened all the galleries slightly and did a bit of whittling elsewhere. (The purpose of the work was to create a street engine of over 500 HP and keep it easily drivable.)
Probably the most significant change to the oiling passages was that we bored out the cam tunnel, re-grooved the bulkheads, and pressed-in a set of roller cam-bearings. Since the necessity for lubing the cam journals was negated---rollers are easily lubed by splash---ALL the oil could be directed to the mains.
I used a C4 PI block. The lifter silos were set for oiling---the fore/aft galleries were drilled at the factory---but the little tower in the back of the valley had not been opened. We drilled there and then tapped for set-screws. Now we had oil for the solid roller lifters.
We used screw-in plugs everywhere and restricted the top-end oil with drilled set-screws at the head-block interface.
In every case, the work done was at the suggestion of the engineers who directed the FE performance program in the first place.
KS
