Is the gm3c tank without filler neck the same tank as the gm306c and the gm307c. I know the 306 (monte carlo 4.3 tbi) and 307 (buick gn) both have a filler neck. Basically wonder if there is a difference in the baffling. Im going to reuse my filler neck because I've read that the spectra filler neck spits gas back out at you when fueling due to poor ventilation.
