recently i purchased another cosworth with a nice engine spec until recently

came home the other day and the car just dident sound the same on tickover
so i compression tesetd it and all the borese exept number 3 were on about 130 psi and number 3 was on 80 psi

my engine spec is low comp and is 7.4 , studded block with wrc headgasket ,ported and poished head with bd 10 cams

so i take the rocker cover off and have noticed some rocker caps are loose and the nuts have neally come all the way off ,and which has caused some studs too strip out off the head

so i carry on and take the head off as no real problem headgasket and stud reusable
i was expecting too see something wrong but everything looks ok
no valves look bent and no bore sacrapes and pistons look ok

any suggestions too what could be the problem

as i have been told the tappet could be stuck or drained off oil due too the rocker bolts being loose which whould cause loss off psi in bore 3

any help or info much appreciated

head being sent in too get studs sorted that have stripped and also check the valves over