ok, im trying to figure out if the magnum block will work with the old LA heads. i want the use of the upgraded valve train, but i dont want to port and polish another set of heads for $300. (the ones i ported are to 340 X head spec). Money is a small issues, but im capable of doing most of the work myself if any modification is needed. from what i read at another website, the magnum block is the same as the oldstyle block, except it has provisions for the roller rockers and oil-through-pushrod oiling system. am i missing anything else?

While the LA heads will physically bolt to a Magnum block, there are other issues to be aware of, as you stated already such as oiling provisions, etc. I think the motor mounts might possibly be different as well.......