I just put the tank back in my 79 this weekend and thanks to advice from another thread used a product called putty tape. I purchased it at a mobile home/RV sales place. Cost was under $5.00 for at least three times the quantity needed and it comes in the appropriate light grey color.
I also replace the stepped hose on the in-tank pump. It's available at International Auto Parts, part # 17018, but like Capp said, at $39.50 I doubt you'll like the price.
'79 Spider Veloce