1963 loud clunk when starting

My initial suggestion was to pull the starter and check for wear on the starter gears. Make sure all the electrical lines (battery connections) are connected and the other lines are also. The solenoid may be going out and is sticking or holding up engaging until the last second and thrusting the starter gear into the flywheel after it has started to turn. Does this clunk go on every time you attempt to start it or just when it is a cold start?.

Well the first time I heard it it was while the car was indeed about to start. With no success on the first try it CLUNKED again even worse this time while the car still appeared to be trying to start. Finally the third time no starting sound at all just a very loud clunk. After taking your advice and looking into the starter we found that it was cracked! Like a huge piece had completely broken off. While removing the starter no shims were found. The mechanic that we've frequently used has a habit of half-assing just about everything. So no shock there. We've been that without the proper shimming the teeth in the starter? won't align right causing this . But now. ..the new starter sounds great and the car DID start up again very briefly but will not stay on. I notice that the fuel filter is empty o_O It has freakin CRUMBS in it! Last I remember there should be fuel kind of guzzling through it. ??

And thank you very much for your time and advice (; I think this is great! :D

I really hate this post. Move off an you lose a lot of typing. Js0816 has good advice. Pressurize the gas tank after removing the gas line from before the fuel/gas pump. Make sure it is running clear. Catch the gas in a clear glass jar and let it settle to see if there is trash in the line/tank or water. If there is a lot, then possible removal of the tank to clean it is recommended,along with blowing out the lines. While your at it, I'd recommend a new type gas filter in line after the pump to make it easier to change out. The old filters were to catch condensation, not junk. Old cars were very easy to work on, not only simple design, but seeing and reaching areas needing fixing. The metal castings were bad and broke easy, that's the gall back. Back when they were new, replacement parts were not expensive, and plentiful. Enjoy your Chebby man.

You guys are so awesome (; I'm enjoying learning about my car. I've been saying that I need to be the one taking care of it :) Well this new advice gives me some stuff to do! Thanks again and I will post the updates!

Well the first time I heard it it was while the car was indeed about to start. With no success on the first try it CLUNKED again even worse this time while the car still appeared to be trying to start. Finally the third time no starting sound at all just a very loud clunk. After taking your advice and looking into the starter we found that it was cracked! Like a huge piece had completely broken off. While removing the starter no shims were found. The mechanic that we've frequently used has a habit of half-assing just about everything. So no shock there. We've been that without the proper shimming the teeth in the starter? won't align right causing this . But now. ..the new starter sounds great and the car DID start up again very briefly but will not stay on. I notice that the fuel filter is empty o_O It has freakin CRUMBS in it! Last I remember there should be fuel kind of guzzling through it. ??

Sounds like you have a crummy mechanic. Of course you changed the filter. Keep an eye on it as there may be more in the tank/lines.

There should be an inspection plate just behind the fly wheel on the bottom to check the teeth on the flywheel. Your going to get greasy, so take some cleaner, old rags, and some grease cutter and clean the plate as much as possible before attempting to remove it. If you have access to a lift, it will be a ton easier to do.