Complex sentence: The GTX was available with the standard 440 four-barrel carburetor, as well as the 440 +6 barrel (three two-barrel carburetors) and the 426 Hemi.
Split into simpler sentences: The GTX was available with the standard 440 four-barrel carburetor. Optional were the 440 +6 barrel (three two-barrel carburetors) and the 426 Hemi.