first off the head gasket & spray bar have little to do with one another?..Here's the best idea for the spray bar...get a new crush washers...then take a 1/16 drill bit & be careful & drill thru one of the corner of the hex..this way you can take some .
.030 monel safety wire & torque the "banjo bolts" & then run the wire thru the hole & around the bar & they will never come out again & no flat camshaft...i have been doing this for many years & charge 75.00 this includes a valve adj. & new gasket! this the only & best I have seen...I have seen the factory banjo bolts with the lock tite on them floating around under the valve cover!!!