fishy, exactly what information do you have? Is this the father of John William Maclean? Is it from the marriage certificate of John W Maclean to Brenda Ford?
If so how old was John William when he married? And what was J A D's occupation? Did John William give his address as 447 Moss Park Drive? If so, how do you know it was his father's address too? And if not, where did the address come from?
The deaths index at Scotland's People does not list a J A D Maclean. (There are an ADJ, two DJAs, and a DJA.) The only marriage of a J A D McLean was in Edinburgh in 1922, indexed as James A Dietric to Gwenllian Cattel-Jones.
The easiest way to find this out would be to look at the Valuation Rolls and/or (even better) Register of Electors for around that time. However this would require a visit to somewhere where these are available, for example the Mitchell Library in Glasgow or the National Library of Scotland. Probably also the British Library in London. The other Copyright Libraries should also have them, I think.
The Register of Electors would tell you what the J stands for, and the names of any other voters in the household, for example his wife.
The other avenue you could pursue, if you know how old John William was in 1964, and assuming that he was born in Scotland, is to look for his birth certificate. The chances are that he was born less than 100 years ago, so you would have to go to a Scotland's People Centre to do this, for example the Mitchell Library in Glasgow or Register House in Edinburgh, because only births over 100 years ago are available online.
There are four John William Macleans and five John William McLeans in the Scottish birth indexes from 1917 to 1950. One of these Macleans and one of these McLeans each have a second given name.