Zed Head

I've wondered about that. The FSM's don't show 3.36 until 1973, in the PD chapters. The image I posted is from the 1972 FSM. But. The General Information chapter shows a 3.364. Errors in the FSM. It's backward. I think that the 3.7 ratio is hard to find. Probably have to go 3.9. Good luck.

If you ask a company that sells "upgrade" parts if you need an upgrade they'll probably say yes. Many people that know say that a better flowing exhaust system (not headers, just the pipes from the manifolds to the back) gives noticeable results. The Pertronix won't change anything, it's just a points replacement. More less maintenance than performance. You probably have a 3.9 now, so 3.7 would be going the wrong way. I would get all of the original parts working correctly before deciding anything. You might be surprised.

Is it a 4 speed? Have you given it a tuneup and checked that the distributor is working correctly? The advance mechanisms inside, both vacuum and centrifugal, are important during the transition from idle to acceleration.

I do notice one odd thing in your video. You seem to have the cap on 180 off. I'm not sure how it would be possible if the square metal locating piece is installed. Can't really tell in your video if it's there. The breaker plate screw holds it in place. Maybe it's on the other side and the cap was installed correctly. Can't tell. Part 18 in the image below. And you didn't tell brand or source. Plus you didn't show it with the spring clamps in place. They can be hard to get on. I used to use a long screwdriver to lever against them from the side to get them to snap in to place. Couldn't get my fingers down there.

Post some pictures. Each ratio actually has two gears, one on the mainshaft and one on the countershaft. Datsun Z Transmission Gears, Speedometer Pinion (5 Speed-...

The original went for very low money. Surprising. $14,000 The modified one barely got a parts value bid. RNM. $5,150

Are the cap and rotor of the same brand? Where did you get them from? Post more pictures. Rotor installed, cap installed. I remember having a rotor that was loose because the spring inside was weak.

Hate to be a buzzkill, but, to keep your brain working on the real cause, the fuel tank is not designed to hold pressure. It is vented to the carbon canister.

Here's an example of the aftermarket parts. I'd just use the factory rubber. Better ride. https://www.rockauto.com/en/moreinfo.php?pk=6397113&cc=1209226&pt=7532&jsn=448

The factory bushing is rubber formed around a metal tube. Aftermarket PU replacements are a separate tube with two PU bushings. The factory part has metal teeth on the ends of the metal tube. Looks like the rubber might have left your bushing. The tube can be difficult to remove from the control arm. Big pliers or vise-grips might be necessary. https://www.tascaparts.com/oem-parts/nissan-bushing-rear-55555e4100

Uh oh. It looks like the clamping bracket has fallen off. You can see the threaded hole for the bolts. You'll need the bracket and the bolts. @Terrapin Z might have what you need. Parts 70, 46, and 47. Bracket, washer, bolt. Here's a few pictures from BaT. What should be there. Better check the front also, looks like it's loose or gone also, allowing the displacement. The diff mount crossmember does the job up there.

Leave the hose off and run the fuel pump by removing the starter solenoid wire and turning the key to Start. See if any liquid comes out of the nipple.

That sounds like a blown/cracked diaphragm in the FPR. Take the vacuum hose off of the FPR and see if it's wet with gas.

This is a not uncommon sign of a failing ignition module. Get ready...

It should mean that. The 78 TIU uses a plug so you should be able to just take a look and see if it's unplugged. If it's still there, I'd leave it just in case you need to go back to it. I'd also take a look at how the Energy-Pak is wired in, for future reference. It pays to be prepared with these old cars.