Sell them both, get an airgap.
https://www.summitracing.com/parts/edl-7576/make/chrysler
https://www.jegs.com/i/Edelbrock/350/7576/10002/-1?year=1968&make=DODGE&model=DART&submodel=GT&engine=V8+%28+5.6L+%2F+340+%29
https://www.amazon.com/Edelbrock-7576-INTAKE-MANIFOLD/dp/B000CN54LK/?tag=fabo03-20