If you are going to install headers on your g body with the olds 307 there are a few things your going run into. The oil filter and housing (!get an oil filter housing gasket!) needs to be removed along with the starter and the torque converter cover. You're going to have to bend the metal vac lines on the sub-frame on either side of the oil pan. Also get some washers for the power steering pump bracket where it bolts to the header on the right bank. make sure you reinstall the torque converter cover before you bolt the headers in. That's all the information which could have saved me an hour at the shop. Other than that good luck with the old manifolds (use 6-point sockets, 1/2" and 9/16")
