Welcome to AF!!
Your engine has 351 cubic inches not 350. May not sound like much but there is a big difference in that the 350 is a GM engine not Ford. That said, I would recommend the Autolite plugs. The Bosch +4 plugs are a gimmick and I have never really heard of anyone having good luck with them. As for getting to the plugs I can't advise you because I have never worked on this model of vehicle. I suggest that you also change the plug wires at the same time. They will break down due to age and rob you of performance. Also, the fuel filter should be changed just because of sitting around for so long. Good Luck!