Zed Head

Before you get too far you might as well find the ECU. The brain box. It's over by the driver's left leg, behind the kick panel. It controls the injectors. Unless you're planning to run carbs.

One of them is incorrect for the diff then. That's just the way they were built. You can see it in the eBay picture and in the illustrations. One is longer than the other. That's why you get the same result when you swap them. Because yours are the same length when they shouldn't be. If you bought the diff used it might be that the seller popped the axles out for storage and gave you a mismatched set by accident. I used to have several R200's and I stored them with the axles removed sometimes. Anyway, in short...your stub axles should be of two lengths, not one. Good luck.

The seller says it was put back to original color. The pictures of when it was red show green on the firewall and the floor. Overall, in the comments, there is much enthusing over a pile of parts. A shiny paint job will do that.

Pictures would help. When you say yoke do you mean flange? And when you say yoke again do you mean "stub axle"? Nissan calls them flange assemblies, most people call them stub axles. The original axles are of different lengths, side to side. Sounds like you're rebuilder might have put a long one where a short belongs. Notice the different part numbers from the carpartsmanual. https://ebay.us/m/jAyp3m Datsun Z Differential Gear, Pinion & Cover (R200)

Perfectly? That seems unlikely. It's odd enough that a British thread pitch would be used on a Japanense car in the late 60's/early 70's. Why would British be used on the block and US on the balance tube? Chaos! Your thread chaser might cut some new threads though. People have used NPT in the oil pressure sender hole and made it work. Soft metal will distort.

Here's a puzzle for somebody. Comes with a car cover. No reserve. https://bringatrailer.com/listing/1971-datsun-240z-330/

Read the articles here about the GM HEI module, if you find that your wiring is smoked or the factory Transistorized Ignition Unit (TIU), aka ignition module, is gone. You can run wires in the engine bay directly from that terminal block with the green and red wires. https://www.classiczcars.com/articles/electrical/

Is BSPT a possibility? The prevailing internet Z forums' "wisdom" is that the oil pressure sending unit holes are BSPT. JIS VS BSP: What's the different ?Before choosing a suitable thread standard, it is necessary to understand from various aspects. This article will introduce the difference between JIS and BSP, so that you can better choose the thread

Sounds like you're saying things have been just fine then something changed. As opposed to the brakes having always bothered you. If it was mine I'd find the source of the sudden problem before "upgrading" anything. Otherwise you could add the upgrades and end up with the same problem, never solved.

They run up to the ignition module. The module uses the signal from those wires to know when to create spark. Looks like this. Has many wires connected to it, including those green and red ones.

Pre-Fleetwood Mac Fleetwood Mac.

Here's a decent relay instructional video.

You can add a relay as cgsheen suggests, which will take the current to the solenoid out of the switch, or you can bypass all of the inhibitors and other safety features. I would start by checking for voltage on the wire that comes from S on the ignition switch when you turn the key to Start. If there's none there then you need an ignition switch. If you have voltage then you can add a relay or by pass each safety on the path to the starter solenoid. It would be best to also test under load, using a test light that draws some current, like a taillight bulb. I have found that the staked pins (copper color) can get loose and lose contact with the terminal. I had a 78 switch that would grab the starter then let go as I turned the key. The pin was loose. I fixed it with a hammer and a chisel. The terminals are marked with molded in letters. Look closely if you remove yours.

Edit - the author apparently didn't know that the history was documented and easily verified. @Carl Beck From his web site - 1975 - Sold to Kenneth E. Logan D.D.S. - L.A., Calif.. Driven for a couple years then stored away. 1998 - Sold to Michael W. Pretzer. Michael decides to continue his education and sells to Carl Beck. 1999 - Purchased by Carl Beck - who will restore it to original "BRE Racing Trim" 2007 - Restoration to "As Raced" condition completed

Odd story. Purchased and restored to street form by a dentist. " : in the garage of a dentist who had purchased it in ’73 and returned it to its somewhat original street-legal state. " The show is next Sunday in Florida. Ponte Vedra Auto ShowPonte Vedra Auto ShowThe Ponte Vedra Auto Show | Sunday, November 2nd 2025. Presented by O'Steen Automotive Group, Art 'n Motion, & St. Johns Chamber of Commerce.