different between crapload vs shitload

English

crap +? load

crapload (plural craploads)

See synonyms at shitload § Synonyms.

shit (large amount) +? -load

shitload (plural shitloads)

(vulgar, slang) A large amount.
- 1980, Robert Zemeckis & Bob Gale, Used Cars
  Roy Fuchs’ Assistant: I just heard there's a shitload of used cars coming this way.

(an unspecific but large amount): arseload (vulgar), assload (vulgar), buttload (mildly vulgar), crapload (vulgar), fuckload (vulgar), fuckton (vulgar), metric shitload (vulgar), shedload (euphemistic), shitful (vulgar), shit-ton or shitton (vulgar)
See Thesaurus:lot