The A740 was the number used for the dual carriageway link between the M8 and the A761 at Linwood, which was opened in November 1968 by Norman Buchan, Joint Parliamentary Under Secretary of State (per the 1968 Scottish Development Department Report). The road is now the eastern end of the A737, and the A740 number has now disappeared for the second time.
At the time the A740 was built, the A737 still ran through the centres of both Johnstone and Paisley, and joined the A8 in the Ibrox area of west Glasgow. The A761 ended at a T-junction on the A737 between Johnstone and Paisley (now a roundabout).
The A740 was a completely new 1.5 mile road, dual carriageway all the way, from the M8roundabout at J10 St James Interchange (renumbered as J29 in the early 1980s), through to a new roundabout on the A761 at Linwood (Linclive Roundabout). It finished just a couple of hundred yards from the gates of the Linwood car plant. Previously, all Linwood traffic had been taken right through the centre of Paisley. The large roundabout on the M8 was already lopsided before the A740 was built, as it had been designed to take the Johnstone Motorway, part of A Highway Plan for Glasgow. The roundabout on the A761, at the western end of the A740, does not appear to have been built ready for a grade separated extension when built in 1969, from the evidence of one-inch maps, however it is very clearly shown on the later 1:50,000 sheets. The westward extension came in the early 1990s, with nearly two miles of new dual carriageway around Johnstone and a further three miles of new single carriageway to join the old A737 west of Howwood.
The dual carriageway was also extended eastwards, with a flyover to avoid the large roundabout at J29, and finishing at a new junction on the M8 - J28A. The west facing slip roads at J28 had to be removed, and were lengthened on either side of the motorway to reach the roundabout at J29 instead. This extended dual carriageway was given the A737 number right through to the M8, with the old A737 route through Johnstone becoming the B787, and the A761 number extended along the old route through Paisley to Ibrox.