BBC News - Indian firm Tata, owner of JLR, wants to improve productivity at its Castle Bromwich plant in the West Midlands by having compulsory Saturday working.
Workers rejected the plans in May, but will vote on them again later.
Tim Parker, from the Unite union, said "We want the investment for this plant, new models and 1,000 new jobs."
As well as introducing compulsory Saturday working, Tata wants to introduce alcohol and drug testing for staff.
Unite had previously recommended the deal to its members in May, but it was rejected by 64%.
'Significant life events'
Mr Parker said discussions had continued with JLR and he was "confident" workers would vote in favour this time.
He said: "We've gone back to the company after hearing workers' concerns, we've won new assurances and safeguards, we've got key elements of control both with the shop stewards and the company on how this will work.
"We've looked at things like significant life events so that if people can't work [those days] they tell us and they won't have to work."
JLR is to build a successor to its previous sports cars, called the F-type, at its Castle Bromwich factory.
It will launch as a two-seat convertible with petrol engines and the design will be based on the C-X16 concept which was unveiled in September 2011. The car will go on sale in mid-2013.
