Is there any different rules for converting a character from Deathwatch to Black Crusade if my character is interred in a Dreadnought?

Transferring Characters : Core rulebook page 281.

Note that some skill, talent, combat rule, weapon quality etc, has changed from Deathwatch to Black Crusade

Also add a special rule from the Helbrute:

Tome of Excess page 108.

Crazed: (0) Wp test when suffering Damage (-10 to the test for every full 5 point of damage). If Failed: Charge the colest enemy if they are charge Range also become Frenzied.

If there is no enemy in charge range the character spend a full action and attack twice with all of his ranged weapons the nearest foe or ally.

After it i think you can play but as always ask and work to gather with your GM.....

(maybe do not select archetype and keep some special rule, trait from previous character role, background)

I was thinking of leveling up a Blood Raven to maximum (similarly to making a DH Ascension character) in a Librarian Contemptor Dreadnought, and then convert him to a Thousand Sons Sorcerer Archetype (Tome of Fate, pg. 30-31). Blood Ravens are heavily implied to be Loyalist Thousand Sons, and it would make sense that the Rubric of Ahriman affected not only regular Thousand Sons, but any Dreadnoughts taken to the Planet of Sorcerers too. I figured it'd make a game a bit more interesting. Thanks for the advice, adding that Helbrute rule'd be a good idea.