502 stalling under load

ok, so i have a 99 baja outlaw with a built zz 502 engine. demon 850, lightning headers, edelbrock marine heads. My problem is that when i go to take off, when i get to about 2200 rpms or about half throttle on stick, engine falls on face. If i trim down and tabs down, i can run at 2200 until planes out then mash throttle and whole rpm band runs perfect, even when backing back down and full throttle again. I have ruled out carb by to many things to list from blowout preventers to jet extensions as i thought it wasnt getting fuel when nose up. now im thinking timing? I have no build sheet for motor so i dont know timing was set at. MSD ignition. Just cant figure out why when im taking off it stalls like that until i plane out. Thought it may be engine angle and fuel problem, but not so much anymore. I dont know what degree cam, but i know it is pretty wild. Very lopey idle. Any ideas??? Ive had this for a year and am sick of babying it on plane.

thanks for all the help. great site!