My 68 firebird 400
the fuel sending unit has only one hose connection and the fuel pump has the inlet out and a assume a vent tube ..i caped the vent tub with a vacume rubber cap a few weeks ago and today it cam off and fuel was spraying out thank God this happened at start up in the garage I put a small hose with a bolt in it but it seems to sill be leaking anyone know what the problem is? the fuel pump is a month old....

sounds like you got a fuel pump with a return line port,you need one for a single line system.

The prvious owner had a three line pump like yours. It also had the inlet port pointing at the block, putting a kink in the fuel line.

I switched to a 40601. Solved both problems.

My 68 400 has the sender with both lines for the pump return. Pretty sure it was all original since I found this car that was sitting in a barn since 79...If the sender works just fine, you can just get a pump with one line to the tank. Be sure you use a vented cap though to prevent vaporlock.

I believe all 400 and AC cars had a return (vent line) back to the tank. Topic has come up before. Are you sure you have an original 400?