These may not be legal in your jurestiction.
When your head lights were designed, a great deal of care would've be put into placing the filaments in position and orientaion with great precision, the element has to be in the exact right place in relation to the refector which in turn is focused on the lens, the trouble is when you source the light from any other method other then the standard format of H4 filament bulb, you would more than likely end up with a very poor light pattern dazzling on coming traffic and not illuminating the bits of the road you want.
You would be better off using proper 7" LED inserts like Beans has on his Blue TR7...........and use bloody relays, nothing cooks electronics like a crap power supply!
If you don't want to go to LED inserts, then I suggest using the best halogen bulbs on the market, Osram Nightbreaker Laser.........and you still should use relays!
"Keep calm, relax, focus on the problem & PULL THE BLOODY TRIGGER"
'80 Triumph TR7, '73 Land Rover (Ford 351. V8),
'97 Ford Falcon Longreach 'S' ute,
'98 MG-F, '69 Ford F250.