HOLD ON! HOLD ON! HOLD ON!
First of all, the JP5608 is for the 144/170/200 ONLY! It will NOT FIT the US 250.
The timing chain sets from Australia for the 250/4.1 engine will NOT FIT the US 250.
If the Autralian chain sets would bolt right in, Does10s and Mike1157 would have purchased them instead of making their own from a SBF V8 set, as Mike would have for Classic Inlines.