As well as the cannabis, the defendant also stopped at Maheno to share a joint and a pre-mixed alcoholic drink with his friend, the court heard.
After the appointment, Taylor picked up his cousin who joined them on the drive back to Oamaru.
The defendant spoke on his cell phone while driving, Sgt Cheyne said.
About 5.50pm, Taylor crossed the centre line into the south-bound lane, colliding head-on with Mr Windle.
The next three vehicles in the convoy then became involved in the collision.
"The defendant stated in explanation that he looked down then looked up and boom the crash happened," a police summary of facts said.
"He acknowledged he crossed the centre line but could offer no explanation for his actions."
While his client admitted the charges, defence counsel Andrew Dawson said not all the specifics of the police's summary were accepted.
They would need to be hammered out before sentencing in February.
The crash occurred on State Highway 1 near the intersection of Apes Rd, about 5km south of Waikouaiti, on a busy Friday night as Queen's Birthday weekend holiday-makers left Dunedin.
Mr Windle's vehicle, two other custom cars and a late model sports car were all travelling south to the run when the crash occurred.
Damaged vehicles were strewn across the highway after the crash and Mr Windle's Ford ended up down a nearby bank.
Mid Winter Run participants who displayed their cars in the Octagon told the Otago Daily Times Mr Windle loved the 1937 Ford Cabriolet convertible in which he died.
Danny Bisschop said Mr Windle had lived in Dunedin in the past, before moving to Kaikoura, and was about to move to Christchurch. He described the semi-retired businessman as a "great guy".
In court today, family of the victim asked Judge Noel Sainsbury why Taylor had not been charged with driving under the influence of drugs causing death.
The judge said it was a police decision and not something over which he had control.
Judge Sainsbury referred the matter to a restorative-justice convenor and told Mr Windle's family it was a worthwhile process to go through.