1977 T140v Coils

your 77 should have come with points and a mechanical advance. if youre still running that, then separately-wired 12volt coils are appropriate.

if you have switched to an electronic ignition like boyer or pazon that fires both plugs every 360 degrees, then they will run better with series-wired six volt coils. but 12volt units in series will still work.

i have a BSA i installed a boyer into and i kept the 12 volt coils because i am a lazy sod and the new 6volt coils are still in the box. it runs okay but i am not pushing high rpms out of it