L.A 360..Magnum ?

Sounds like a good combo for sure. Are the Promax heads decent and is it better to buy bare . I would assume to 4 inch scat kit with cast crank is fine
Bare? Only if you know setup, have the tools and have a cheaper part source and still be 'quality'. If not, buy complete.
Figure
Springs
$70-300 elgin/comp/pac/herbert/isky/
Valves
$98-400+elgin,ssi,ferrea,milodon,engine pro,etc
Locks
$19- 40 comp super
Retainers
$35-54 comp
Seals-
$12-20 good ones

So it depends on what you are doing..whether or not it's more economical bare or complete. As PBR said ..they do good work. Great product.