I think in the case of a tie the first party (Liberal or Conservative) to make a coalition with the NDP would form the government. I'd wager that even though Stanfield's Tories were no where near as far ideologically right as Harper's are today, and the fact that they shared a good deal of their platform with the NDP, Trudeau would be quicker to offer a much bigger slice of the pie and thus win the support of the NDP.
In the case of a Conservative Minority, as previously mentioned, the Tories of 1972 shared a good deal of the NDP's values (albeit for different reasons) I could see them holding together a Blue/Orange coalition for a few years, but it won't last as the NDP's pro-labour stance will eventually cause them to split from the Tories. That being said the Conservative/NDP Coalition would be able to do a number of things such as prevent planned tax increases, institute wage and price controls to curb inflation, increase tariffs etc. Stanfield, being a Red Tory, might even be persuaded to go along with the creation of Petro-Canada in order to placate the NDP and stay in power.
The potential creation of Petro-Canada might just be the issue that brings down Stanfield's minority government, causing the Alberta wing of the Conservatives under Joe Clark to split from the party and form a populist alternative. Or if Stanfield attempts to court the Albertans' leads to the defection of the NDP and the subsequent collapse of the government.