3406b exhaust manifold gaskets

so im doin another set of these manifold gaskets, got 2 yrs 4 months out of em , 1 blew out .... noticing mabe some rust pits on head .... has anyone double gasket these to take out any imperfections?

 

ya i put a straight edge it was out.... i took to a local maxhine shop they shaved it straight again ... i was in a pinch hoping this works for now....

 

i believe ur rite wore out ill be due for a manifold ... stock or aftermarket? preformance? whats ur opinion? .... allso im not sure if anyone has had this but the last 2 kits i bought the spacers are either to long or the studs aint long enuff??? if i seat the stud install manifokd n use the supplied spacer there aint no thred left to put a nut or at least go all way threww the nut

 

ok well that makes that easy... im fine with stock, yes i got lucky, gye who bored a bbc like 15 yrs ago for me , shaved this in 2 hrs for me for 200 cdn cash , 15 min from house had it back in 2.5 hrs, i never seperated it , he said be harder to clamp to machine? idk.... its done and on in a day so i can at least get rollin and next time plan on a manifold new... centering pins make sence i allmost grsbbed some 3/8 hard plastic air lone to slide over stud to center but just kinda held it in zapped it

 

wore out.... im just lookin at my pics my head is round port and ex manifold is square?