Okay, here's my 2 cts from an old mechanic. Can you see where the flexplate is rubbing against the starter? If so can you take a picture and post it? Some part must be wrong, I have never seen a 289/302 flexplate rub a starter, did the 302 come from a car with a manual transmission, if so, did you remove the pilot bushing from the center of the crankshaft? If the engine is a 68 302, then it should have a 28 oz type balance weight and should look like some of the pictures of them. Your starter should be a 2 bolt mounting type starter, there are 4 different starter drives used on starters, if the flexplate is hitting the starter drive, depending on where it is hitting you may need a different starter drive. There is a spacer that should be under the heads of the bolts that go through the flexplate into the crankshaft, you didn't put the spacer next to the crankshaft by mistake? What transmission are you using, is it a c4 automatic for the 67 year, or is it something else? Please provide more information, too much is better than not enough, we will sort through it for what we want. Good Luck.