How to implement 8-bit 2:1 multiplexers on a PCB?
The 74HC298A is more expensive (Digikey has it for $5.81, while the 157 is around $0.70) but it was designed for 4-bit data lines (instead of 4 1-bit data lines), so it has a much friendlier layout:



You may be able to route the traces for input 2 upwards and squeeze C1 between D1 and D2. With some luck, this might extend to two of these side-by-side.