piston slap is common on all 2WD cossies due to the center gudgeon pins.
most high performance pistons get it as the center pin is better for high revving engines..

no real damage will happen as it only lasts for a little while when cold...

some manufactures still use it, and the noise is classed as " acceptable "

some pistons expand over that of the " norm " so have larger bores and get slap from that .....

as long as it is piston slap due to this and nothing else its fine.....