New plugs and wires.... How about putting it on #1 cyl on compression, 15 deg BFTC, and then checking your cap order in relation to the rotor, and then double check the firing order of the wires going to the plugs?
IF you are looking for a big project and the floors aren't too bad, around $2k. They are pretty nice cars fixed up, and it was the Indy Pace Car for '65.
First off, if the carb is mech secondary (I didn't look yours's up), switch to vac secondary carb. Unlike many on this site, I like Holley's, but on the street for a performance 318 I would be running a traditional 1850 vac secondary 600 cfm. The carb size would be fine with the vac controlled...
I've been running headers since the mid-70s and have run many brands. They all seem to have one to a few close tubes. I have been using the heat proof sleeves on the close tubes for a number of years with good results. There are a number of manufactures that you can buy from Summit or another...
Worth a try for the new unit. The couple of 50 year old limited slip units I redid recently needed parts and one needed machine work to run true. I like running less back lash than I see many on these Mopar sites run, but in order to do so, the runout must be minimal. I did a couple others...
You people saying 3.23 gear max, ever have a car with more gear? I've driven thousands of miles over the years with 3.5-3.9 gears, and a fare amount on the FW going to shows and tracks. If your cooling system is right, 383/400 motors don't mind it a bit, only down side is the worse gas...
Ya, you'll feel the gears in the seat of your pants, and if you have a set ready to go, just an afternoon to change out. I drove a fare amount last year on a 3.9 set up, about 3k rpm on some FW driving at 60mph and my 400 BB did fine, of course it will depend on your tire size for your rpms.
Besides insuring the timing and carb are tuned, change to 3.9 gears if you don't need to commute frequently on the FW. The 383 will like and handle the rpms just fine, only down side is gas mileage will suffer.
Doesn't appear to be a nylon one from the pics. All the ones I've seen have either off-white or tan colored gear teeth. Looks like a typical steel low performance stock-like original or replacement.
I don't know for sure, but who does. In any case I hate down time on a running car, and for me I don't have that much time left, all things considered. If your valves are indeed burned, i.e. pie serving-like sections missing of the valve head, then just as likely the heads are in rough shape...
I would advise pulling at least one valve cover and see what it looks like. If it's just has a coffee colored film over everything, that is better than if it has a heavy caked deposits filling most of the valve cover, (usually from only adding oil and never changing it). If really heavily...