My 59 apache has a 69 327 in it. It had a q-jet which had burned in it's past life and was literally disintegrating, so i swapped it for a new Holley spread bore with elec. choke and vac secondaries. When I start it up the idle is fine, it will drop correctly when i blip the throttle. Once I start driving when i come to a light it will not drop down to the correct idle but will race a bit. When I blip it again it drops back down to a nice purr. Any suggestions? it's disappointing as the truck runs a thousand time better. Very responsive with lots more pep. I've checked the linkage it's not binding, it has all new linkage bushings and springs.
Thanks in advance,
Greg