I wouldnt bother with Schumachers. I've repaired several that broke. You want to make sure teh left side ofthe engine can't lift much. I say much, becaseu I dont like solid mounts. Too much feel for my tastes and it's broken blocks that way. I use about $10 of chain and turnbuckle from my local hardware store on anythignn that runs bigger tires. It's not the power, but the resistance to that power in the form of traction, that loads the mounts. Stock 318s wil lrip brand new India/China/Mexican produced stock mounts. In 4sp cars that can leave you because the Z bar slips off the pivot ball, and the linkage flies apart. (been there personally a bunch before I got smarter). You dont want a solid trans mount, and I dont want a single solid mount.. Because I've had blocks loose ears from them. Maybe tohers dont botl as tight? I dont know. In any case, the chumachers use a U shaped bracket that over time will fatigue and break if you're really making power. Use the interlocking mounts, and you really only need one, or a torque strap that will not hold the engine motionless, but doesnt let it rise more than about 1/2". Drive a fast shaker car with good tires and you'll see how far the engine moves normally. Gliddeen doesnt want the weight of the engine pulling the iron out of shape. When the engien is settled in place, the rear is held by the trans mount, and that 40% of the egnien weight is distributed around the whole bell area. The ears support the remainder 60%. So each mount is really only seeing about 300lbs on the block ears. That's next to nothing, and the position of them (far forward and high on it) means the torque has the least amount of leverage when pulling against them. In the beginning, I'd wagger the only reason they are that far forward (and in the way of steeering) is the clearance required for starter and T bars.
