This is an average quality header gasket as sold by budget vendors.
Since we work on so many roadsters, we know that changing the header gasket is a pain and suggest using the best gasket you can buy!
We suggest these instead:
https://www.datsunrestorationproducts.com/product-page/exhaust-manifold-gasket-1600-1500
Low cost Header Gasket 1600/1500
$25.00Price