If your not gonna drive it on the freeway put the 4.56 in it if your gonna drive on the freeway some put A 4.30 in it and don't drive over 50. I had a 4.11 with 26'' m/t steet slicks on my 69 camaro 355 w/12 to 1 comp. and about the same cam you have w/205 Dart pro 1 heads 60cc with a Victor jr. & 750 holly @ 3700 #'s and a 4 speed and it did great. for street racing red light to red light. no freeway use 4.56 for sure. 3.73 to 4.11 may be a waist of money. HAVE FUN
Andy