Apparently the manifold revealed a deeper problem with the engine position that I didn't have a clue of.
The engine seemed to be tilted backwards and very close to the firewall.
On top of this, the rubber mounts were unusually stretched.
Most probable reason is the installation of a 131 gearbox (without remote shifter) by the previous owner without having cut the propshaft tunnel. He just made it a little wider at the gear lever hole and to be honest, I am really happy that the tunnel is intact.
Since the propshaft of the 131 gearbox is positioned higher than the 124 one and the tunnel was not cut to compensate this height difference, the engine was pulled rearwards and tilted backwards by the gearbox.
What had to be done was either to change the gearbox or to find a way to place the engine back to its original, or at least close to its original to position.
The solution came by searching the market for mounts that would do exactly this.
We managed to find a pair of mounts that seemed to be ideal for the task as they moved the engine slightly to the front, for achieving the desired firewall clearance for the manifold, and slightly lower so that the gearbox and propshaft would be aligned.
Now it seems that everything sits better than before. The engine is flat and not tilted and the gear lever reposition was so insignificant that there were no modifications necessary.
The exhaust was not such a big problem either. The Y junction was obstructed by the new engine position but when I took the car to the exhaust shop it was revealed that the Y junction itself had been previously modified. We installed a NOS from 124 Special T and it fitted like a glove!
New aftermarket engine mounts (Rear thread was cut)
Current engine position with the swept-back manufold in place and K&N filters
Exhaust manifold with the NOS Y junction in place.