x2 My Duster would run 13.0 with the 3.91 and I was running the .484 cam. The only "lightening" I did was remove the rear seat for the roll bar and that added more than removed. I ran a 750dp and a 904 rmvb. It was also a 72 with the lower compression 340 that had never been out of the car or had the heads taken off of it since new. So get that SG in there and you should have no problem smokin that guy.