Bularian superheavyweight Antonio Krastev set a junior world snatch mark in a record-tumbling day at the American Junior World Weight Lifting competition in Bethesda yesterday.

The 277-pound, 18 year-old Krastev, who is far ahead of Soviet legend Vasily Alexyev at the same age, beat his junior world snatch record of 180 kilos (397 pounds) with a lift of 185 kilos (408 pounds).

However, Krastev failed in an effortto clean and jerk 222 kilos (491 pounds), which would have topped his record of 220.5 (487 pounds). Krastev easily took the gold medal in the superheavyweight division with a combined total of 375 kilos (826 pounds).

Krastev's teammate, 113-pound Janya Sarandaliev, also set a junior world record with a clean and jerk of 132.5 kilos (292 pounds), breaking the mark of 132 kilos held by Zhang Yuexin of the Peoples Republic of China.

Sarandaliev, 19, predicted he will be the 52-kilo world champion lifter in 1980. "My goal is to establish a world record that cannot and will not be broken for many years," said the cockey, yet stolid, Sarandaliey

The other momentous event of the meet was the 163-kilo (359 pounds) clean and jerk by Washington Tony Sims of the Crushers Unlimited Weightlifting culb. The lift broke the American junior record of 162.5 kilos held by Michael Cohen of Savannah, Ga.

he 19-year-old Sims, who won the 75-kilo class gold medal, said, "I can't believe it. I'm in the books. It's amazing, but really I'm not satisfied. I won't be satisfield until I go to the Olympics and win there."