i know this would have been done to death, but im looking at get some new wheels for my 71 Bug, now since i cant find any wheels that are 4x130 (thats our stud pattern isnt it?)

But i will be looking at getting the blank disc and drums drilled to probably commodore stud pattern (only because there is more choise of wheels)

but what is the biggest size you can go?

any help will be great

What - wheel size??

Depends

First off - are you a 71 super or 71 standard??

I have seen 18" x 8" nder stock guards on a super

Offset is what matters

What width rim are you after??
V Force sell a 6" x 15" 36ET that fit nicely in 4 x 130PCD

All these 4 bolt wheels fit to some degree
http://www.pelicanparts.com/techarticles/914_wheel_types/914_wheel_types.htm 

anagin - offset is what determines what will fit properly

i have been told its a super. flat screen, not elephant footprint tali lights, metal dash.

under the adrs one inch bigger and wider than the biggest available.
so 16x6 technically but ive got 7s on the rear of my bug

i was actually looking at putting on some commodore chaser wheels

make sure of your offset or they will stick out of the guards and not be legal.
also with wider rims you may need to change to smaller diameter struts on the front.

With the best offset 5.5" is about the best on a super before different springs/struts are required