Cylinder head gaskets
 

As part of my long term project to build a 5.6L version of a 4.5 engine I will need head gaskets that match the 96.5mm bore of the 5.6. I am unable to fine anyone that will modify the 4.5 gaskets with bigger bores and new fire rings and I doubt the bores would end up in the correct places anyway. Custom gaskets are very expensive as they would be on off. The 5.6 gaskets fit fine with a little porting where some of the passages don't quite match-mostly the water passages are partially covered but the cylinder bores, locating pins and head bolts(with the exception of the long cam tower bolts) match fine. They appear to be of different material and are thinner ).049" vs .075". Does anyone have any information on why they would or would not work? Are all aluminum engine head gaskets different than iron block/aluminum head gaskets?
Note: these pictures are from before I had the block bored

Tony:

Mother Benz has acknowledged the design change was to improve sealing. The change came with the 4.2/5.6 engines ('86 MY). Should be even better with the rigidity of the iron block.

Thanks for the info Frank