Depending on stock, Inland may have one that fits. The vent won't be cut out because the tank may fit several years. And yes it will be spendy. So even a new one may need work when you get it.
I would suggest looking at repairs if you are looking for less expensive. Mostrepairs can be done fairly inexpensive. And it doesn't have to look pretty because no one is really going to see it.
1966 Mercury Park Lane 4 DR Breezeway 410 4V, C-6, 2.80 - Streamless.
1966 Lincoln 4 door Convertible 462 4V 1971 Ford LTD Convertible 429 4V Phoenix ~ Yeah it's hot however it's a dry heat!