Micky, the ones I sent pix of were supplied by yard that did restoration back in 96. Wherever they got them from is probably not available today even if they could remember where they came from. Just look and look online. These were bare aluminum vents we set off to be powder coated. With no attachment to any other metals they have held up super. Last resort would be to get a fab shop to make some up and power coat them. They are oversized and cover original opening with plenty of airflow for 2600RPM Cummins 6BT's. Get some old school high quality SS # 6 or #8 screws with barely big enough pilot holes and no stains and will never loosen up. Just a dab of 5200 on screw holes, nothing on the vent.
And if I ever somehow make it to PR I want a ride!