Enigne size in 70's coupe

I just built a 9.9ltr twin turbo engine, with 4 dcoe carbs and twin cams and put it in the 70s coupe body (ford falcon xb coupe style).
it fitted nicely only stuck out the bonnet a little bit, nothing a bonnet bulge wouldn't cover.
I then went to make a NA version of the same engine - just removed the turbos and left the rest the same.
Now it won't let me put it in the car, says its too big.
I needed to reduce it to 8.17ltrs to get it to fit.
It would be nice to be allowed extra height with the engines, then use bonnet bulges and scoops to cover them or have a hole cut out to suit.
it fitted nicely only stuck out the bonnet a little bit, nothing a bonnet bulge wouldn't cover.
I then went to make a NA version of the same engine - just removed the turbos and left the rest the same.
Now it won't let me put it in the car, says its too big.
I needed to reduce it to 8.17ltrs to get it to fit.

It would be nice to be allowed extra height with the engines, then use bonnet bulges and scoops to cover them or have a hole cut out to suit.