Raja Ali's car was rammed and then blocked in at the side by two vehicles in Dagenham on 25 September 2016.
The 33-year-old was then chased and stabbed.
Abubakar Bana, from Hornchurch, Essex, and Jordon Archambie, 20, of Stratford, east London, were convicted following a trial at the Old Bailey.
Daniel Welch, 34, of Winstead Gardens, Dagenham, and Zakar Yunas, 22, of Rokeby Steret, Stratford, were found guilty of violent disorder.
Mussa Jalo, 21, from Norfolk Road, Dagenham, had pleaded guilty to violent disorder at the start of the trial, along with Bana, of Station Lane, and Archambie, of Hesketh Road.
Jurors in the trial heard that Mr Ali was sat in his car along with two friends waiting for what they thought was a drugs deal.
A Mitsubishi Shogun 4x4 then rammed into Mr Ali's car, shunting it forward, while a red Renault Megane pulled up alongside and the occupants got out armed with weapons.
Mr Ali and two other men ran away but they were chased and the 33-year-old was stabbed to death in Braintree Road.
Det Ch Insp Dave Whellams called it a "pre-planned and orchestrated murder".
"Regardless of what Raja's intentions were that night, when he arranged to meet these men he should not have lost his life.
"I hope Raja's grieving family are able to move forward knowing his attackers have now been brought to justice."
All will be sentenced on 3 July.
Two men have been found guilty of the manslaughter of a drug dealer who was stabbed to death after being ambushed by a rival gang.