You can't copy the shape of the Manleys onto the Ferreas; there would have to be material added to make them the same. And I don't think that they have a hollow stem blank that would duplicate the Manley shape, so you'd have to buy the minimum order for a custom hollow stem valve, which is 250 parts. Easier to work with the Manleys, or get some custom titanium valves. I know one guy running the titanium valves and I think he said they were 110 grams each.
Regarding the oil squirters, they are just short, cut off brake line tubes, put into the front oil passage on the SOHC heads. They are not designed to oil the chain; the chain gets plenty of splash, and doesn't need more oiling. The squirters are designed to oil the bearings in the fuel pump gear and the tensioner gear. My feeling is that those may get insufficient splash, so to ensure long life I direct a tiny stream of oil into the ball bearings on these gears.
Quite a while back I did a bunch of extensive dyno testing on one of my SOHCs, to try to determine how much the chain stretched at various engine speeds. This was on a 650 HP engine with fairly mild cams and springs. I set the engine up with magnets on the stub cam gear and the cam gear in each head, and used some high speed magnetic sensors to record the data digitally (my regular job is all about magnetic sensors). What I found was that between 3000 and 7000 RPM, the right cam retarded 3-4 degrees, and the left cam actually advanced 2 degrees. For years afterwards I set up the cam timing on my engines to compensate for that, and they ran fine that way. I saw no need for a gear drive.
Fast forward to last year, with my 577" SOHC on the dyno. I was using a Megasquirt MS3X EFI box for engine control, and it has the capability to accept data from up to four cam sensors. It already has the crank sensor required for engine timing, of course, so I took the opportunity to add two cam sensors to this engine, and log the data with the MS3X. This time, the data looked completely different. One thing I had never been able to check with my original testing was how the cam timing behaved from idle, or cranking for that matter, to 3000 RPM. What the MS3X data shows was an immediate 3-4 degree retard of the cams in this range. And then, in the 3000-7000 RPM range, it showed both cams retarding even further, for a total of 8-9 degrees retard on the left cam, and 12 degrees retard on the right cam.
These values are so far off from my original testing that I am a little skeptical of them. I don't know what algorithm is used inside the MS3X to measure the cam advance/retard, and how accurate it is, whereas with the original data I was collecting the information via a datalogging oscilloscope, and had excellent data resolution and repeatability. But if the data is correct, it is a real eye opener. This engine uses much heavier valve springs than the original test engine I used back in 2006, which would have a significant effect on chain stretch. The cams are also much bigger, leading to more load on the chain. Finally, this engine made the most power with the cams very, very far advanced, something like a 103 degree intake centerline. The cams are ground on 114 degree lobe centers, so if they are retarding 10 degrees or so, then they are straight up in the peak horsepower range, which also makes sense.
This year when I get the engine back together I plan to do more testing to try to nail this down. But if I can confirm last years results, then I think a gear drive might be a big improvement to the engine, especially with big cams and springs.
