Not if it's the same starter.

Ring gear swaps normally needed when replacing the 6v starter with a 12v starter.

If you just put 12v to the 6v starter you get the rapid start. Like Old GMC Gold I have done that to Jeeps, Tractors, Combines, Bailers, etc. for years.

Mikey


1951 Chevy 3600 rust bucket with GarWood dump bed conversion
http://www.flickr.com/photos/mikeybs51chevy