big ends on a 80 series

[crazyclark31]

heya am after some advice on doing the big ends on a 80 series.

Have been told you need to take out the old caps and get every thing measured before you can get the new ones ordered?
Is this right? Was under the understanding you could just buy replacements and fit them without getting the other stuff done?Or am i comletly wrong.
If makes any diff the truck is religiously serviced every 5k with caltex delo400 and has about 350 000ks on clock