[dscott]

The blue #156 wire is for the brake warning light on the stock prop valve. You don't need it for brake lights. The brake lights are activated by a switch on the brake pedal rod where the booster hooks on to the pedal. The line lock should work fine on the firewall by the booster. There isn't enough heat there to make it malfunction. You would need to be within about 2 inches of the header for it to cause a problem.
Don