I guess a plate almost as thick at the Carb base plate should be used. I do not put motors in this way but others I know have but usually a single four intake manifold is used so if for some reason the threads get screwed up then its just a four barrel hemi intake that gets screwed up not a Stage V intake worth a lot more. I like the motor in from the bottom if it is a resto sitting on the K Frame and front suspension but I usually use a motor slider with the bolts either in the heads or a near location without the intake and carbs on the motor. Looks like he wants to put everything in the car as he bought it and just set the carbs on with little or no disassembly of what he has bought. There are plates for a single four that can be bought and can be used on nearly every single four barrel intake set up to install any motor.