440 distributor question

i have a 440 from a 78 motorhome with mild cam running 10.5:1 comp. i can not get the advance timing right. i was told by a Mopar guy that i need to be 28 to 32 degrees total advance but i am getting about 45. i have chnaged the pick up coil and the vacuum advance. i have changed the springs adn still too much. any ideas?
Author: 2002ram440