I have completed the installation of the HVAC system. The 2.5″ SHOP-VAC tubing was used to run the air-flow, and a plate (made of fiberglass) was fabricated – this allowed the tubes to mount to the stock HVAC outlet. This was a time consuming modification – 6.5 hours total.
I’ve decided against the installation the stock HVAC system – it was causing fitment issues with the PISA dash. So I’m going to run a custom venting system using vacuum tubing. More details to follow….