I researched this extensively when I rebuilt my motor. "Stroking" a motor is a great idea, it's good for low end grunt but the piston speed increases because the distance per revolution the piston travels increases with stroke. This stresses out the rod bearings. The rod bearings on a Z are the weak point of an otherwise robust motor. The Z block is also tight so in order to squeeze in a meaning full increase of stroke it would be necessary to offset grind the rod bearings which would decrease their size, further exaggerating the problem of rod bearing stress. To offset the stress you would have to use much lighter pistons and rods. It's very expensive to make a piston light and turbo compatible and one off light weight rods for a Z are expensive. After all this you have to get the motor to balance. Most stoker motors need heavier counterweights on the crank despite lighter pistons and rods because the fulcrum effect. That extra rotating mass doesn’t help performance. I calculated doing all this and the I could safely get to 3.5l, the cost and time involved was astronomical so I decided to put the money in to ball bearing turbos instead. In the past I did stroke and bore a Porsche V8 from 4.5l to 5.9l. The torque was amazing but the motor didn't have any useable power past 5600 RPM
21:15:18 11/16/05
