The A742, the highest numbered A7xx road in the 1922 Road Lists, is no more. It was the continuation of the A78 trunk route between Irvine and Greenock; the A78 used to head off round the coast to Gourock at a TOTSO junction near Inverkip, and the A742 continued through Spango Valley, past the large IBM plant, and descended through Greenock centre to meet the A8. Now the A78 takes this route, and the old A78 coast route is the A770.
Some people think that the A78 and A742 should have simply swapped numbers, whereas the old A78 became the A770 when the former took this route back in the mid 1980s. This road was and still is the direct way to Inverkip from Greenock. The more detailed account below is written as it was in 1982, a few years before it became the A78.
West of Greenock
The A742 started on a T-junction with the A8. The A8 heads towards Gourock, while we head into the outskirts of Greenock town centre and find our first roundabout. We go straight ahead and over a railway before we meet the B7054 on a corner. Next up is the Greenock suburb of Braeside. We pass the railway station of Branchton and signs for Lyle Hill. This is where the Free French navy memorial is. We are now heading out of Greenock and into the countryside. This marks the start of the Spango Valley, where the hills rise to about 500 m. It also marks the start of the planned dual carriageway which is for the new IBM works. As part of the deal to build their factory in Greenock, they are paying for the upgrade of the southern end of the road. We continue to pass between the hills on this road until we meet the A78 from Gourock. This is where the A78TOTSOs to go toward Gourock and thus marks the end of the A742. Just after the road ends, the planed D2 section will end. At this moment of time (1982), though, it is wholly S2. This road may become the A78 toward Gourock, the Scottish Office will decide its fate very soon.
For a up-to-date account of this road as it looks today, see A78.