you'd have to look at the filament setup to see... i dont recall if they're the same on not... from another site.......
***
3157:
category: Miniature
volt: 12.8 / 14
amp: 2.1 / 0.59
watt: 26.9 / 8.26
base: W2.5x16q
glass: S8
filament: C6/C6
fil.res.: 6.1 / 23.7 ohm
m.o.l.: 2.09 inch (53MM)
l.c.l.: 1.1 inch (27.9MM)
burn pos: burn lamp in ANY position
i.lumens: 402 / 37.7
cp: 32 / 3
cri: 99
d.hours: 2000 / 10000
notes:
automobile lamp
base:black nylon
extended service (long life)
code:hd
code:ll
krypton gas
stop light lamp
tail lamp
3457:
category: Miniature
volt: 12.8 / 14
amp: 2.23 / 0.59
watt: 28.5 / 8.26
base: W2.5x16q
glass: S8
filament: C6/C6
fil.res.: 5.74 / 23.7 ohm
m.o.l.: 2.09 inch (53MM)
l.c.l.: 1.1 inch (27.9MM)
i.lumens: 503 / 37.7
cp: 40 / 3
d.hours: 400 / 5000
notes:
Amodel base
base:grey amodel
code:hd
specs verified against ANSI-SR25D1997
stop light lamp
tail lamp
looks like 3457 has more lumens, more watts, etc. i remember thinking that 3157 was for Fords, and 3457 was for Chevy's. i do know that if you put a Chevy bulb in our cars, it will blow the fuses....been there, tried that.
as far as LED's, though...i know most places have a 3157/3457 replacement that works in place of either...and will work in either application.