Using '65 mounts to set the engine back and lower.

Moving the engine down and back lowers the center of gravity and increases balance front to rear. The easy way is to buy a set of RMP mounts  (http://www.ronmorrisperformance.com/miva/merchant.mvc?Screen=CTGY&Store_Code=rmp&Category_Code=Eng_Parts). These mounts are very well designed and built.  The only down side to these mounts is the cost, and the polyurathane transmits slightly more engine vibration to the chassis.  After purchasing the '65 "C" or "A" code frame mounts (both cars are the same) on eBay, the other parts are from NPD.  Total cost, including the 4" wide x 1/4" steel plate is about $150.00.    

Two stages to this. First stage is modifying the left insulator mount by drilling and counter-sinking two 3/8" holes. 

 Using flat face allen bolts to secure the mount

  Nylocks on the top side.

'65 mounts do not have any protection from devulcanization that can happen from torque, heat, and oil saturation. The '66 on up mounts are "captured mounts", but sit 1/2" higher.  Drilling 3/8" holes through the mounts, and using 3/8" flat head allen bolts with lock nuts secures the mount so it won't come apart, while not "preloading the rubber mount.  This way it still maintains stock NVH characteristics, and looks.  I have always done both sides, but it is not necesary.  BTW:  This is a really old "racers trick" I picked up on back in the '70s

To move the engine back, requires fabricating new "L" brackets.  I wanted 5/8" rearward movement, which is as much as I could go without changing the driveshaft (for a third time), or carving up the tunnel where the T5 shifter comes through.  Here are a couple of pictures of the completed "L-Mount".  The front side is gussetted to keep the "L Mount" from colapsing or stretching under the torque.  This is done to both the driver side and passenger side "L Mount". 

  Driver side shown.  Passenger side is similar

 The taper is to allow for P.S. hose clearance from the R&P servo.

It's just a 4" wide piece of1/4" flat stock, drilled to move the engine back further on the mount.  Then an oxy/acetalene torch is used to heat the area of the bend up to where it is cherry red.  The steel flat stock should not take much force to bend.  Once bent the mounts are trial fitted, and adjusted as needed to get the engine centered and longitudinally level.  Once the correct bend is set, the mounts are heated up cherry red, and quenched in 30 weight engine oil.  This puts a light temper in the steel.  The gussets are cut from 1/8" flat stock and welded on.  I weld the gusset to the front of the driver side, and rear of the passenger side.  It's easier to assemble and dissassemble the mounts in the car this way.

 Stock "L Mounts" are 3" wide.  Here you can see the 4' plate and the isolator mount hole moved forward, so that the whole engine will move back. 

That's pretty much it.  I took advantage of the R&P to sit the engine down a bit further than 1/2", so it took a bit of trial and error to get the engine sitting perfect.  this is the second set I made (not counting the store bought ones).