I just built a 302 up (world heads, comp cam .512 lift... bla bla bla, victor jr manifold. holly 650 dubble pumper)

and got it runing... if you could call it runing. it takes a little bit of work to get it runing. fires once, twice, shoots some flames out fires again then starts... It runs like crap. backfires out both ends and has no balls whatsoever. messing with the timeing dosen't help anything. lifters are all adjusted to 1/2 past 0 lash. i was hearing a kinda weird wosh noise comeing from the header which concerns me any ides would be helpful.