Edelbrock Carburetor tuning question...

Personally I would go at least two steps up on the whole rod for white plugs, IF you are fairly sure it's through the entire throttle range.
Does it act "peaky" at low throttle or surge at all?
If not you might just go with a rod that has a smaller top size and leave the lower end the same size.
Obviously there are jets and crap that can alter this through the entire off idle range also, so it would be nice to try to find out if it's just at mid, high, or low throttle only.

Sorry, I meant two steps down (in size) but you probably already knew that. :D