[Paul Sutphen]

I have been told that because the Shelby Alum block uses studs for the heads rather than bolts like the original cast iron blocks, the Shelby heads cannot be lifted off with the engine in place and therefore the engine must be removed. The reason for this problem is that by the time you try to lift the head to clear the end of the stud, the head will not clear the fender. For what it's worth.
Paul