Hi Tom,
To answer your question, I would agree with Michael and suggest the implementation of a 3[SUP]rd[/SUP] brake light as it is usually mounted high on the back of the car and, even when implemented with multiple LEDs, will be viewed much closer on-axis to appear bright. Since the brake light will only be applied when the brake is applied, it will appear abruptly and with no need for a differentiation from running lights.
LED Implementation
I have tried to find a reasonably priced LED for a while now and all those professing a brighter output then the standard 1157 incandescent have disappointed. When evaluating LED implementation cost (LED + resistor or electronic flasher) against the delivered benefits of light and longevity, I have found that the change to LEDs does not deliver the light output, signal differentiation, or longevity (installed 10 years at my cars less than frequent use) for a better economic package.
Please don’t misunderstand. I am not against the use of LEDs, however, I have read and found that LEDs provide bright light … but only when viewed on-axis could the light appear greater then the standard incandescent 1157 brake and signal. When viewed off-axis however, LED light output will appear much diminished the further the viewer moves away from on-axis and will appear much less then its replaced incandescent.
Since the BJ8 Phase 1 and earlier Healeys have a rather low-positioned tail light assembly, the closer a following driver comes to the rear of an LED equipped Healey, the more acute the viewing angle and dimmer its appearance, however, the farther back a driver follows, the more direct the viewing angle and brighter the running and signal lights will appear (less atmospheric distance deterioration). Further, where an 1157 replacement LED is used, the differentiation between the running light and signal light is not as obvious as with an incandescent (the signal light usually provides 2x the output of the running light) and may not provide the brake or directional notification you are looking for.
I, personally, do not see much benefit in replacing my running/signal lights with LEDs and, although others profess satisfaction with LEDs, have not yet found a reasonable cost/benefit to justify their implementation.
Hopes this helps,
Ray (64BJ8P1)