High Claudio,
The "big block" is really my thing. Bust a move on the RC carb if you have to to keep it under 4000 rpm. You MUST use a tach on the Saito because 7000 rpm sounds JUST LIKE 3500 rpm,(trust me, I know).
Here's the deal, first quart 2000-2500 rpm no more!!! Fuel for break-in,(I fly with this) 10% castor 10% synthetic. Do not-repeat, do not use all synthetic fuel on break-in no matter what anybody tells you. When you finish break-in,(and this is the manly part) DON'T just check your valves-readjust them.
Better still, make sure you check your valve clearance before you crank it up for the first time,(Saito screws up from time to time). Do not use the valve shim gauge that comes with your Saito. When they stamp them out at the factory, it leaves a "lip" on the edges that screws up your valve adjustment. Purchase and use a high quality set "Kastor" brand here in the states.
Do not over prop your "big block" on break-in, be nice to it. Get your break-in right and the thing will last damn near longer than you.
Claudio, when you get everything right, and you crank that nose up for your first reverse wingover-I know for me, I thought, "man, this is as good as it gets".