Well first I get a shift point for that engine of 7000 to 7200. try 6800 and work your way up!! those heads really like it up high. you not giving that intake and those heads a chance to show their stuff.
I ran 4.56 on the street with 4.56 gears fine if you don't cruise the highway too much 4000 rpm is 72 mph with 28 inch tall tires. Thes motors will cruise all day at 4000.
2 to 3 tenths for the 4.56 (likely 3 tenths quarter and .2 in the 1/8) shifting it a 7000 will likely net .2 to .3 more ?? but with a 28 inch tire look for high 10's but 7000 out the end.
Perfect for your motor would be 29.5 slicks with the 4.56 or 4.30 gear and 28 inch tall either would still give 11.00's at 6800 out the end