I'm shooting for 250-300 at the wheels with the 3.4 s/c'd i'm building right now <img src="/forums/images/graemlins/lol.gif" alt="" />

Well, in those dyno runs it's in open loop, maybe you are having issues with closed loop? remember, all they are doing there is flooring it, not part throttle cruise/w/e. It's closed loop where you are having an issue.
Are you running an NGK/denso o2 sensor?

89 4Runner
3" BL, M/T locks, 33"bfg mt, bilstein, Kayline, tubebumper, toyotafiberglass panels
TBI: Elocker,3.4 w/ORS,b+b,S2Sstg2cams,arias pistons,P+P intake,TRDs/c,URDpullies+7th,downey headers,MAPECU2,WEGO WB, SupraMAF,walboro255,stg4clutch, EPaOo2 sim