Rear leaf spring question

Im considering new leaf springs for my 68 Valiant(360 orig /6)
The V8 springs have a 5/8 bolt front bushing, While the /6 car has a 1/2 bolt bushing.
I have the 1/2" bolt bushing. Can I drill the spring pocket to 5/8 or is there anything else to consider.
At general spring there is a 50 dollar difference (the 5/8 being less expensive). otherwise they appear to be identical