You did not specify if you are running cast iron aluminum heads. There are different coolant passages in the different Cometic part numbers and they are based on which head you are planning to run.
Magnum block and LA block can be treated the same, just order correct gasket for the head.
@pittsburghracer previously mentioned ordering his Cometic gaskets through 4secondsflat.com and they help make sure the correct style is selected. That is how I plan to order my next set.
