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I'm so freakin' sick of oil squirters being given credit for everything.
First issue with any engine and RPM is connecting rod strength. Coupled with the con rod strength is piston weight. Light piston/strong rod are a must.
Next issue is the valvetrain. The amount of force the springs need to apply to the valves goes up exponentially with speed (as does all speed/energy equations - think back to the pistons) Strong springs and/or light valves/retainers/keepers are needed. Cam followers are also a sore spot on our engines - they're good to 7000 RPM or even a bit higher, but with enough RPM they'll toss the shim out from between the cam and lifter bucket and wreck everything. Solid lifters with lash caps are needed.
The bigger diameter a bearing is, the faster the bearing surfaces slide past one another for a given angular speed. Said another way, our big freakin' B21/B23 bearings are haulin' ass past the crank at 6500 RPM, let alone 10,000. What's the big deal about this? The oil between the bearing and the crank "shears" (ask an engineer) as the crank is rotated, and depending on the viscocity of the oil, a certain amount of energy is absorbed, in the form of torque resisted by the bearings. This torque can tear the bearings out of the rods and/or block. Smaller bearings are ALWAYS found on high-RPM motors.
Windage must be controlled within the engine too. Windage is where oil is sprayed around, getting whipped to a froth by the spinning crank, flailing rods & pistons, and all the air movement within the block. Squirters are the LAST things you want!!! Windage trays, crank scrapers, internal baffles... these will help keep your oil in a liquid state and in the pan, where it can be used to lubricate your engine.
You've also got to investigate things like the strength of the flywheel/clutch - can they withstand 10,000 RPM? I doubt it. What about the belt speed? I'm guessing the force trying to fling the belts off the pulleys will do just that. Deep groove pulleys would be needed.
Now that the bottom end is strong enough, you can start looking at the cam, ports, manifolding, and everything needed to supply air to this high-RPM monster you're bench racing with.
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