Gas smell...
A '76 Fiat should have a sealed system. The gas cap should not be vented by design or by previous owner modification. Check that the cap seals, look over entire fuel system, especially at the carb. Plug any uncapped nipples on the carb and car for now in case they are venting. Check the charcoal canister and tank vent lines.
If it was overfilled, you could have leakage at the tank fill neck etc., but it should dissipate. Also check the tank sender area. Any original hose should be replaced anyway, but look around all the hoses especially braided cloth covered ones for wetness.
A '76 Fiat should have a sealed system. The gas cap should not be vented by design or by previous owner modification. Check that the cap seals, look over entire fuel system, especially at the carb. Plug any uncapped nipples on the carb and car for now in case they are venting. Check the charcoal canister and tank vent lines.
If it was overfilled, you could have leakage at the tank fill neck etc., but it should dissipate. Also check the tank sender area. Any original hose should be replaced anyway, but look around all the hoses especially braided cloth covered ones for wetness.