Thanks for the feed back. I think 2004R is the way to go for me. I live in Southern California and I use the freeway a lot. I would like to relieve the engine some stress during high speed cruising by lowering the RPM. Well, since the posting is gone, I guess I'll have to wait for another chance. I am in no rush. There are other things for me to do with my 68 bird. I am fixing to install headers. Thanks to you all.