The strength is exactly the same. What matters is the distribution of light is much improved. 

> On Apr 6, 2016, at 10:14 PM, Brent Weide <brent.weide@gmail.com> wrote:
> 
> Folks:
> I'm about to embark on the upgrade of the 1991 square 9004 headlights to
> the early vanagon H4 round headlights and would appreciate  your assistance.
> Does anyone know of a way to accurately measure the improved lighting using
> every day tools?  I'd like to measure that headlight strength before and
> after the change.
> I'll be documenting the change (good or bad) on my website and appreciate
> your feedback.
> 
> All the best,
> Brent
> --
> Brent Weide
> Portland, Oregon
> www.weidefamily.net/vanagon/