273 4bbl, carb replacement?

champion 12 or 14 for late smog motors
but the LY series works best to eliminate the idling (and smog)( and missing) problems for these motors
carbs/ MAKE IT WORK
what you have
AVSII
TQ
small primaries and big secondaries
do not worry about an AVSII or TQ being "too big"
the Air door limits the size