If the head has been decked you may have issues with piston to valve contact with both Ape and Kibblewhite valves, they have a much thicker face, you may not get enough clearance using cam timing alone. The OE inlet valves are your cheapest option on G1 & 2 as they are steel and around 50 US a valve. They as far as I know are not on back order here, but you would get stuffed on import taxes. Have you thought about a second hand head to strip out for the best 8 of 16 intakes? Why do you need a new tensioner? You can get a new gasket from Cometic in the US.