Do an
Engine leakdown test and make sure you aren't leaning it out with a leak. Search around for the how-to. Also known as crankcase leak test, or pressure test, etc.
When it stalls out, have you pulled and examined your plug? Is it very light colored, beige, brown, or black?
Do a plug chop and verify your jetting at idle, 1/2, and wide-open. Search around for a plug-chop how-to. Very simple and important. Or you can use an EGT gage if you've got one plumbed in, but the chop is simple and fast.
What altitude are you at? This may have a factor on your jetting.
What octane fuel you running? Oil?
What fuel/oil ratio you running?
Any mods to the Engine, or is it bone-stock?