Need info on slant six engine

After looking over the car more after I got it home it seems to be better than I thought. I found some paper work in the dash says it has Clifford header, offenhouser intake and a 600 holley.It is a 4 speed with heavy duty clutch pressure plate and tb.Also has ss springs and 8 3/4 posi with 3:55 gears.A previous owner took it to brewers in ohio and had a lot of work done. Dont know if they did anything else to engine.