just fitted a agg bottom end and big valve head to my mk2

only 2 real problems to report and question!
1). after the oil had burnt off the exhaust manifold, i noticed ALOT of oil collecting on the inlet manifold. its ok because the inlet doesnt get hot enough, but will still like to get it sorted. is the only place this can come from the rocker cover gasket?
2). it started first time, and once i got over a water leak or 2 and got driving the car was very flat, and hesitates at 3k in every gear. now i havent a timing light at the moment, but i think it may be a tooth out somewhere?
its real flat, and real slow until 5k, where it pulls strong to 6k, then runs out of revs. it also backfires on most gear changes. im thinking the cam is a tooth retarded and needs advancing a tooth, as everythings happening a lot later than it should
any advice would be great, Paul