what is the difference between the l31 and the lo5 block and how can you tell them apart visually.

 

i don't think there is any difference in them really. i am starting to see a serious pattern of people worrying about which block they get. as long as you get a block that has no cracks or anything in it you are in good shape. most blocks cast after 1987 have the provisions for the roller cams already drilled adn tapped and the blocks that are not drilled and tapped still have the raised spots to put the holes in. many truck and marine application blocks were not tapped and most of the passenger car ones were.
any 350 block will do, especially if you intend to swap cams and stuff anyway.

later
tim