Yes 67 cuda has "mylar lockstrip" pricey and a shitty 1 year design(we have a 67).
Changing to 68/9 is a wise choice.
BUT pricey. Go with a "Precision" 68/9 gasket. Pay the $$.
So gasket, clips, stainless trim.
@69FBCuda has trim for sale.
@RPM440+6 is a good member here and a distributor. He can hook you up with gasket/clips.
Dont get sucked in with cheaper parts for this. Use a quality gasket(Precision). Like I said rpm440+6 will give you the straight goods.
