Clark,
I've shortened Model-A pitman arms with good success... why not make a longer V8 one out of 2?
What i do is cut a real long V in the arm so you have the most possible weld in the joint... bevel it out deep and gradually build up the weld... let it cool slow
in the end I usually hammer my weld a bit and then smooth and sort of polish it to eliminate any tight areas that may let a crack form...
you could even gusset it on the outside then afterwards for extra security if you wanted...
I know some people say never to weld on steering components... but if you do it right... it'll be alright
good luck!