66 Barracuda 273 Intake Manifold options?

yes the LD4B IS a direct swap for your manifold and will really wake up that 273. The LD4B was specifically designed for the 66 273 ( before an LA 318 was even offered). The only modification needed is that there is no provision for bolting the stock coil bracket to the manifold so you either have to mount a universal coil bracket to the firewall, or use the coil bracket for a 340 six pack which is offered widely. The latter solution requires a bit of minor massaging to the bracket which mounts under the back two intake bolts on the passenger side.