here, the first syllable of pasta usually rhymes with car.

I would say the brits pronounce the first syllable to rhyme with fast, but as some yanks would give that two syllables (fay-ast) so that doesn't help
Clod, the "master" comparison doesn't always work either because some brits (southern pooftahs) would pronounce that to rhyme with American "pasta" and some (northern bastards) wouldn't