[Old Guy with 87 GT]

the *stock retainers are different and won't work with the crane springs .........i recently purchased the same springs ,but i got the crane kit that comes with the retainers and locks(part #44308-1) ............the stock retainers are conacal and are different for the intake and the exaust valves (the spring heights are different and there a different design )

if you got the retainers that crane recommends for the springs then they should be fine ......they designed there parts to work with the stock valves .............but .....although the locks arent that much different from the stock ones ,they effect the springs installed hieght ......you have to install them and then check the spring hieght .......they should be within specs ,if not then you'll have to shim springs or get different locks

on mine i had to shime the intakes like .030 to get the instaled height ,then on the exaust valves the spring hieght was to high and the locks in the kit didn't work with my roller rockers (the rocker would have hit the retainer ),so i had to get different locks that lowered the springs hieght .050 .....on the exaust valves with the different locks my spring height was good without any shims

been running the set for about a month with no problems