So I was thinking the other day how I don't have mds on my truck because it's a 5 speed 3/4 ton but I do use the engine braking a lot so I got to thinking what if on my new engine I am building (392) I took 8 MDS lifters and put them on just intake valves and wired the solenoids to a button I could push when I am engine braking to shut off the intake valves, would this create a higher vacuume in the cylinders and more effective braking like a jake brake for a gas engine or am I not thinking something through properly here? I could even wire in a cutout to the ground on the injectors so they are not filling the port with fuel while the intake valve is not opening and get the added benefit of not using any fuel while it's not needed (yes I am aware I would get a code for an open circuit for the injectors).

Doing that would put pressure on the piston going up and act like a spring to push it down so net braking would be minimal. Of course thinking more about closing the intake valve would do the same thing butt with a vacuum pulling on it. The first stroke with the closed valve would be the only stroke to brake the truck.