I'm looking at some new wheels for my '65 notch in the not too distant future.
Have my eye on some and am trying to figure out if they'll fit inside the wheel arch or not.

Is the standard wheel size 15x4.5 with an offset of 46mm?

The new ones I'm looking at are 15x5 inch with an offset of 20mm.

From my basic understanding, it'll stick out towards the fender about an inch? The distance to the suspension will be increased though?

Would this be too much to fit inside the arches with 165's out back and 145's up front?

Cheers

use this to help calculate the changes

http://www.1010tires.com/WheelOffsetCalculator.asp 

Cheers.
I like this like better though : http://www.rimsntires.com/specs.jsp 
Hopefully it helps someone else out also.

I've figured out the spacing/size difference ~26mm. Just wondering if anyone has had first hand experience with fitting a similar size/offset wheel in the past. Bloody offset! why can't everything come in 40mm+