Wayne - the alt shouldn't affect the signals, you've got some other wiring messed up, or there's bad grounds somewhere - you need to check/track all the signal/tail light wires and make sure they're correct - can't say exactly how it should be, but sounds like you've got the alt hooked up right - someone here will link a wiring diagram for the conversion

Bill

Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics