ok, so leaving the leaking issue aside, try this :
I understand that you used the standard engine mounts of the boxer engine and gearbox in your Nova.
So this should mean that you have :
1 - The engine/gearbox mount on the top of the houser
2 - the front mount that goes on the crossmember section
3 - the rear gearbox mount that bolts onto the chassis
( I'm not mentioning the side mount under the engine as its not important for the angle )
So , temporary solution and testing time :
Take the two number 13 bolts off from the front that sit the engine on the crossmember.
Then take a jack and hold up the engine between the box and engine right under the middle top mount to keep it at its correct height.
Take off the two bolts that at the tail of the gearbox that hold it up and loosen the top engine mount so it can tilt.
Use another jack and lift the nose of the engine up to the angle that you need.
Then take a thick plate of metal and put it between the front lower engine mount and the crossmember and then cut two pieces of metal pipe and use them as spacers for the rear of the gearbox mount.
If you then tighten all bolts up and therefore have the desired/proper angle, make sure you can still get into second fourth and reverse gear and take it for a drive.
If all your problems have been solved, then you can make those mounts more permanent
....writing all these down, actually gave me an idea ! ...what if your front mount is broken and the engine is sitting lower at the front than it should ??? This would give you the same problem !!! It has happened to me a couple of times in the past as the front engine mount can separate the rubber from the metal quite easily. It could be because of the materials they used, or it just didnt agree with my driving style