300SD engine refreshing
 

I'll soon be pulling the engine from my cosmetically challenged 300SD to put into a very clean 420 SEL. It's running great, but needs oil leaks fixed, plus I plan on replacing oil pump chain/guides, also timing chain/guides,front and rear main seals while it's out. It has around 300K on it, uses no oil.
Is there anything else I should be looking at while it's out? I know the replacement chain needs a special tool to install.Is the actual Mercedes part an endless chain? If so, how bad is it to put in?Is it worth the extra work? I would assume the crank and cam gears have to come off(I'll be checking them for wear also),but how about the injection pump?