273 to 383 swap

the last swap i did was a 440 from a 1969 Chrysler that came with biscuits with a single bolt, into a 1966 Satellite that had a 273 that came with biscuits with a single bolt, straight bolt in! that means that the single bolt on both sets of biscuits have to have the same measurements between them to fit, and therefore would fit the same in any k frame that had either a 273, 318, 383, or 440 single bolt biscuit, aside from inner compartment size restrictions. this brings me back to my original question, the 1967 barracuda didn't have p.s because of manifold clearance problems, so i'd like to know if Schumacher mounts shift the motor slightly from the p.s. to allow the drivers manifold to clear, or are they just new stock mounts, and they sell you headers to get around the clearance issue!