i have alot of experience on push rods engines specialy old school toyotas,but im going to install a set of gsc s2 and want to degree them at gsc recomendation of 107in /113exh.should i take the measurements at the valve retainer? if so, what about the lifter lash?

 

take it at the retainer... make sure that you bleed down all the lifters before you degree them in...

 

could anything go wrong if you dont bleed them? I know about "lifter tick", but what about possible lifter failure?