Captain Obvious

Your place was a hammer farm back in the old days?

And about the spring... My spring was a little rusty nugget. Pretty much nothing left. I got a couple locks from junkers and adapted one of them to fit my lock. Unfortunately, I don't remember what the donor car was, which makes the suggestion mostly useless. But, here's a pic. My rusty nugget of what's left of my original spring is at the top, and two donor springs in the foreground: I ended up cutting the "double" spring into two pieces and using half of that one. Again, my original nugget in the lower left:

You are correct. None of those marks on either side of the main groove are supposed to be there. And JB weld will fill in the grooves, but best case, I don't think it will last long. And worst case, as it wears away, it gums up the works. I would just do the best you can with what you have and pretend you never saw those small grooves in the first place. I mean... If someone wants to break into the car, that lock won't stop them, even if it's new.

The radio I have is from a later year. It has the later (horizontal) antenna switch design. I assume a PO changed it out at sometime in the past.

Here's some pics of what I have here. These are from a mid 70's car. Map light connections on the car side: : And on the light side: Here's the lighter: And here's what I believe is my antenna switch connections? Seems I have a pigtail leading into the three position connector everyone seems to have? This might be an early car thing?

The anti-backfire valve is supposed to be closed tight shut when there is no vacuum on the control signal port. If you apply enough vacuum to the small control port, the valve should open and pass air between the two large hose connections. And the control port should hold vacuum and not leak down, but I have seen them function "well enough" even with a small leak in the control cavity. Bottom line... It sounds to me that you unfortunately have two failed AB valves there. Neither of them are any good.

Understood. But it's a matter of AVAILABILITY, not performance. There is no performance change at all. It's more of an "unfortunate necessary substitution driven by inability to get the better fitting part". The OP asked if the 73-76 cylinders were a good upgrade, and I believe the answer is "no". I'm not trying to cause any trouble here.

Chas, I took a couple pics of the radio area and will post them when I get a chance. In the meantime, here are a few things to look at: First, As drawn. there is no power being supplied to the accessory relay or ignition switch. You need a connection dot on the W/R wire: Second, the map light and lighter have black wires coming off them to make connection to ground. I have pics of these wires, but they were never shown well on the original documentation: Third, maybe I'm misunderstanding the intent of your drawing, but it appears the heater blower motor appears twice in two different shapes:

I'm not totally sure I understand the question, so I'm just gonna shotgun a little: It's not 73 and up. It's actually 73 to 76. In 77, they changed the wheel cylinders dramatically. So... If your question is "Should I change to the 73-76 cylinders?", then my answer is "No. There is no "upgrade" to making that change at all." So unless there is something wrong with your current cylinders, there is nothing to be gained by changing to the 73-76 style. And if your question is "Should I change to the 77-78 style cylinders?", then my answer is "The 77-78 style cylinders are way better than any of the previous years, but changing over to them is not an easy conversion."

First, some answers... For the 71 four-screw lids, You should be using the 18.5mm long valves. So what you are using there sounds fine. The target float level for the 71 lids is 20mm below the lid, but I believe anything close (18-22) should be fine. When I went through the same thing, the only solution I could come up with was to add weight to the floats. This 4g brass plug threaded into the side of the float worked well:

Thanks Chas. I looked through my pics and don't have anything good, but I believe the three connections to the antenna switch are three independent spade connectors on three loose wires. I'll confirm when I get a chance unless someone beats me to it. I'll work on the "vintage" style diagram and you can work up the "new style color" version. Might just be me, but I'm finding working on an early car is enjoyable using an early wiring diagram. Cleaned up and corrected, of course. Kinda quirky. So how would you like me to communicate mistakes on your diagram? Screen shots? For example, like this:

Thanks Steve. I'll make that clear on my wiring diagram when I'm making the next batch of changes.

And I have a question... On a future revision, I'm intending to clearly show the coil and ballast resistor on the engine side of the bulkhead firewall. But what about the reverse light switch. Do the wires going to the reverse switch on the transmission go through the same firewall bulkhead out towards the engine, or do they go through a hole somewhere else? I haven't looked for those on my car, but hoping someone here knows off the top of their head.

Glad you're still around! I spent some time looking at the details of the power distribution system and cobbled up this sketch: And I made some changes to the wiring diagram I've been messing with. Here's the latest: <V3.0>

Here's the latest. I swapped the gauge locations and made a couple other small changes. Please let me know what you think: <V2.0>

@Namerow So independent invention... Here's what I've been messing with. I cleaned up and modified the diagram from the BE section of the FSM. Biggest changes are adding the accessory relay and it's associated devices (heater blower and rear defroster). Lots of other smaller changes, most of which you identified in your notes. I will make additional changes based on stuff you found that I did not such as the incorrect labeling of the gauge functions (didn't see the forest through the trees) and it seems there are some issues around the combo switch area where documentation does not accurately depict reality.

Oh, and the existence / non-existence of the accessory relay... I was wondering if maybe that was a build date issue, But if you have the accessory relay on your 4/70, then even if it was added after initial release, it was added pretty early.

Namerow, So here's my assessment at this point... I should have asked earlier because I independently found most of the issues you noted on your markup. Asking sooner would have made that easier. Those issues are why I was expressing frustration with the documentation. One big issue, however, is your interpretation of the power going through the "F" fuse. That fuse feeds FROM the ignition switch, it towards it. The rest of stuff (turn signal flasher, and gauge power) is fused. And of course, that also means that the comment about the fuse block nomenclature is also incorrect when you said that top row are all power-out with the exception of "F". The entire top side IS power-out, including "F". And many of the problems I turned up still exist in the color version. Maybe @EuroDat can pop in here if he caught wind of this tread? This could be an opportunity to make that document better.

I found that exact situation when I was looking for a spare for my car. Now granted, I was limiting my search to donut space saver spares, but I had fitment issues with the front brakes. The little drums in the rear were fine, but I was hitting the caliper up front. And my car, being a 77, has the reduced size spare tire well. You don't have that complication.

What he said. Hope you found the root problem!!

Hmmm... Try one. It might be OK. The diameter should be fine. The only thing that might be an issue is the width, but in theory, you're less than .400 inches wider than stock. Maybe you're looking at a non-problem!

Thanks for the files. I'll look that stuff over and see how they look!

What he said. In fact, I wouldn't even deal with a tank... I'd just fill up the float bowls with a piece of tubing and a funnel. Round tops will run the engine for 30-60 seconds before the bowls get sucked empty. I would hope that your carbs would be in the same ballpark.

Just wanted to pop in and say glad to help.

Why won't a full size fit? I thought the 75 had the big spare well? They didn't change to the smaller spare tire well until 77.