Carter 4 Barrel Top Cover Leaking

On my 67 Barracuda, I got the original Carter AFB - 4295S rebuilt. rungasket materals and perfoms great. However after i drive it and put it back in the garage I noticed a strong gas smell. come to fine out the gasket for the top of the carberator in the rear was leaking. I went back to where I had it rebuilt and they retorqued the screws but it continues to see what seemingly appears to be wicking through the gasket material. Has any one encountered this? the shop suggested we double up on the gaskets using two to maybe address any imperfectons in the surfaces. I haven't wanted to take it appart to inspect it till I had a replacement gasket. does any one know of a source to get just the gasket I need without buying a whole kit at the $110 plus or minus.

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