What I found was the 1157 is a two filament bulb. The 1156 is single filament and slightly less wattage which is OK with me since I rarely have any of my old cars out at night. Randall as to talking about my car not being "correct" I left that several alterations ago. I have 3 TR-3s. Two original and then this latest project. Mustang II front end, IDIDIT steering column, Currie four link rear with posi, Chevy small block 350, GM 200-R4 automatic tranny, huge fiberglass rear fenders to accommodate 225/55/16 Goodyear Eagles on wide Dayton wire wheels. BUT from all apprearances it lo0ks like a standard TR-3. Back to the topic of electric it also has a HOTWIRE wiring harness.