How do I determine which grade of Aluminium

[RonA]

My old car restoration continues apace & Ive just had the wings/running boards fettled. I have two parts of the louvred bonnet in Aluminium, normally these were in steel but mine are off a racing version of the car. As you can see from the pictures they’ve been a bit butchered & are not a very good fit around the steering box cover.
Ideally I’d like to have a couple of pieces of Aluminium sheet welded to the edge of the butchered section. Any idea how I’d go about determining the quality of the Aluminium & filler rod req’d. The process is a bit beyond me but I know somebody who could do the job for me.
RonA

 

[500e]

Ron it does not look a fit in other places rad cowl line,, rear to wing, would it not be easier \better to make a new panel & get some one to do the louvers.
I have done louvers by hand with a routed hardwood form

 

[RonA]

Ron it does not look a fit in other places rad cowl line,, rear to wing, would it not be easier \better to make a new panel & get some one to do the louvers.
I have done louvers by hand with a routed hardwood form

I your looking at the rear end of the louvred panel the body wooden side rail goes in there, it is actually a good fit to the radiator.
RonA