The hood bulge was a factory item , created for drag racing Fords.
The 390 is a 6.390 Centimeters Cubed
It would be a 406 which Ford used for racing approx. two years before switching to the 427.
I just searched Wiki for the variations of FEs. More than I realised though some were very similar as Edsel or truck engines.
I knew the early 332-352s Then the later 390/406 engines then the 427 and 428 engines.
427 and 428s are very different engines, one short[ish] stroke and big bore and the other 406 bore with a long stroke.
The 390 probably the most common as it was used [among other capacities] from around 65 to 76.
My new for 71 Galaxie LTD in the US had 2 and 4bbl versions of that engine along with numerous others from 240 6 through to 429 Cobrajet. In Oz we [reputedly] had 302W and 400 2bbl. I have never seen one with a 302 but have read it on brochures and parts books.
Even in 62-68 they had numerous versions of the FEs.
A local bloke with a 63 Galaxie coupe has fitted his 390 4bbl engine with the tripower 427 set up. Quite a quick car. And those cars are light at around 1700 kilos,, my 71 400 C6 a/c car is 1.990 tonnes. Simply a full size family car. The big cars weigh over 2 tonnes.
Another I know [its co owner worked for me] is a factory 66 7 litre manual car. Big lazy grunter with bull nose Top Loader and Kelsey Hayes 4 spot brakes. I suspect as a road car far nicer all round than the 427s.
Though I would adopt either!!