The pump looks like a Tokheim 500 to me? Find a good welder in your area. These guys, if good, can cut in a piece of steel to fill the void. Then you can use body filler to blend for painting. Paul
www.severngaspumps.com I cant find any pump tops that look like this. I see that some tolkheims have the double light bump outs on each side but they look different like tgere are light shields hanging lower on them.
As far as welding I tried with my Mig which does not work on the cast metal. I guess you can weld on cast but not with y mig.
Dave