The capability to "tune" the fuel mixture along the complete range of throttle and engine rpm can make EFI better. Look at Tune-up and mileage over the years. Especially how long spark plugs last.

1. Points/Carb. Tune ups every 10K miles. Performance drops unless you kept the points adjusted. Replace plugs, points and usually rotor, check cap and wires. Adjust timing. Build up on plugs.
2. HEI/Carb. No more points, reliable spark. Tune up needed every 10-15K
   Replace plugs, rotor, check cap wires. Timing adjustment rarely needed. Build up on plugs. Resister plugs become the norm. Along with many pollution controls and many more vacuum lines on the carb.
3. Throttle body/HEI. Tune ups moved to 25K. Replace plugs, rotor, check cap wires. Light buildup on plugs. Performance returns after Pollution controls kill the carb.
4. Late model port injection, crank fire ignition. Tune ups moved to 50-100K miles. Many cases near 0 buildup on plugs. Performance better than ever.

When switching to EFI and justifying the cost, the key is how well you can handle the EFI and mate it to your engine, shift points, gearing etc. "Saving money" with an EFI system may be many miles down the road on a hobby car.  Other starting and running benefits may make it worth it.

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