Tunnel ports were absolutely made in aluminum as I have two original Ford sets of them. They were definitely used on GT40s since this is why Ford cast some of these heads in aluminum.
I’m looking for a pair of 5DS25-1 differential side plates with the cast lug on them for bolting to the bell housing. Contact me at (702) 449-4447 or email me at [email protected]
Thanks,
James Cebe