Re: Neck of a soloist Body of a san dimas
You need to be more specific about the particular models.
I'm guessing you mean a Jackson Dinky neck, right? Soloist are neck-thru guitars so no neck replacement is possible.
Dinkies are usually 24 fret guitars vs the 22 fret San Dimas Strats so the neck is not a direct replacement, you'll have intonation problems.
Even if the neck can be properly set, the high fret access would be awful as San Dimas Strats are not designed for 24 fret necks.
If you want a Strat shaped guitar with a pointy Jackson headstock you should look into the old Charvel Model series or get a custom Warmoth.