The dimensions given are from the crank centerline to the outside of the body, and approximate.  You should leave at least three inches between the top of a stack and the window.  Fuel stand-off  and/or backfiring will "soil" the window, so a shield over the stacks is highly recommended.

Engine room
ERA GT MK I:
  • The total length of the engine, from the rear of the block face to the front of the lower pulley, should be less than 27".  Note that the crankshaft centerline height determines the pan depth to a maximum of 7.25".

MK II:

  • We make an indentation in the bulkhead, allowing another "1 to 28".  Remember though, that the water pump pulley intrudes into the passenger compartment by 2" on the small block and 3" on the big block.  The seats are designed around this hump, but any larger hump will present comfort issues unless you are shorter than 5'8".  The original MK II used a dry sump to maintain the crank centerline height.