if you have to use a small block chev use the 400 block,350 crankshaft because it has counter weights and is stronger . dont use the 400 heads as the bowtie heads are shit, use 350 double hump fuelie heads or a set of performance heads from an aftermarket manufacturer/supplier, there are pleanty availiable in the states then just work your way along from there. or buy a book on hotting up sbc's.