3406B truck engine

The injector lines connect to some sort of union that passes thru the head then the fuel lines to the injectors connect to them . Sis shows orings on them unions . Friends truck has some that are moving in the head is the o rings the only thing that holds hem in place , sorry i dont have serial number or ar the tags are all gone . Waiting to see if peterbilt can get me the original engine info its a 1989 pete if i remember correctly .

3406B truck engine