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Hi all, I've been dealing with some heatsoaking issues on my setup. I have a holley 390cfm 4160 carburetor on an Arizona Z car manifold and aftermarket headers (unknown brand) in a '77 280z with the stock L28. I'm not sure who else is running this setup, but I know it at least used to be somewhat popular, so I figure most of the issues have probably been figured out, but I haven't come across much information on solving heatsoaking issues with this setup. There is no room for a phenolic spacer, as the air cleaner already contacts the hood when closed. It's a 2in air cleaner, and it doesnt look like theres a way to reduce that height to squeeze a spacer in there. I have a heatshield between the headers and manifold, but that only helps for continuous driving. If I ever park for between a couple minutes and an hour or two, it still heatsoaks and I get a super lean AFR. To mitigate this, the best thing I've found is just running jets that are way too big, but then I'm obviously running too rich when I'm not heatsoaked. Size 62 jets seem to put me at a healthy AFR when I'm heatsoaked, but I really should be running 52 or 53 jets for optimal AFR. I don't have a fuel recirculation setup, so it dead ends with the carburetor. I'm doubtfull that this would help a ton, since the carburetor itself has no fuel outlet, and by running a lighter 8.5 power valve in the holley, I can lower the AFR under WOT sometimes, leading me to believe most of the vapor lock is in the carburetor metering plate. I'm considering trying this anyway, since I don't think it'll hurt anything. I'm also hesitant to try a heatshield like this one, as it adds height, even if I skip the smaller plates and only add the main heatshield, and as I mentioned, I'm already contacting the hood at the vent. How much has this been an issue for other Z owners running a 4-barrel setup? How impactful have fuel recirculation or the Jegs style heatshield been for other setups? What solutions have I not found yet? Thanks

spent the last few days focusing on fixing some steering geometry. If you guys remember this car came with the 240sx knuckles and if you've ever done any research on that swap, its hot garbage. I spent some time adusting ackerman right off the bat and made it so it was drivable and made a small adjustment last week. My plan has always been to modify them and get all the geometry dialed to how i like it and then scan it. and make a billet version that is modular and can be tweaked in from there. Anyway. This weekends goal was to dial in the mechanical trail and some roll center correction. The 240sx knuckle on the wrong side of the car made the mechanical trail very large so the car had very very heavy steering feel. I did some measuring and made a decision. Clipped off 8º of angle off the ball joint mount. and offset the mount to where i wanted it. Designed and machined an adapter block and welded it on. came up with a quick bumpsteer kit as the knuckle needs to have the tie rod mount lowered by a good bit. didn't take good photos but the car drives SO MUCH BETTER. steering feels great. "light" (for manual steering) but centers still centers well and has good feedback. Took the wife to get ice cream last night and what a great feeling that was after a year of work.

08-23-2026 ATLAS Z UPDATE. Today was another tough one. 4+ hours in getting the clutch master cylinder rod screwed in to the custom clevis on the pedal arm and then everything bolted back up, adjusted and set up. VERY hard for me to get in there, and I am old, so it is a ball breaker. I knew it would be and put it off for months, today I did it. I managed to get the trim piece I mentioned yesterday painted silver and then after the clutch, I tackled the next issue. I don't know how, but there is no bar from the brake pedal arm to the switch so the brake lights will come on and go off. So, I simply took some sheet metal, bent and hammered a 90 and then with a sharpie and my angle grinder cut and formed a piece that I am bolting to he brake arm, that will stick out and push the brake light switch closed when the pedal is released. I drilled 2 holes through the arm and this sheet metal bracket It's hanging up painted and will be install with 2 1/4X20 bolts and nuts. After it was done it was time to relax a bit with a couple Coors and look around, I taped one of my atlas emblems to the front corner of the hood. I don't know If I will use it there or not, I can either paint it flat black to contrast on the gloss powder coat, paint it datsun metallic blue like the engine compartment, or I don't know, any ideas?

Picked up a drill press on marketplace and started drilling into this thicker metal for the engine brace. Got the two pieces that will connect to the engine mounts drilled and bolted up to the engine to try and figure out the angles to attach it to the brace. I made some marks and will cut it and drill it next weekend. We got a lot of rain so I spent most of my time trying to adjust the front suspension. I got one of these wheel fitment things a few months ago and it was saying I needed some negative off wheels to fit I so started adjusting the track width to get it close to a normal offset. Lots of adjusting the toe/traction/camber arms but I think I got it in a better spot. I’ll start shopping for wheels later this year. I have a set that will work temporarily, but are narrower than what I want.

You've got a PM!

08-22-2026 ATLAS Z UPDATE: Work The Punchlist. Decided to switch it up a bit today and work a punch list of little things I just let pile up working on the bigger ticket items. Started with getting the horn installed, wiring my dual fans in, finished the clutch master cylinder in the engine compartment, topped off the transmission with some redline MT90, then finished the intake pipe, getting the air filter on the end and getting it in there good....ended up having to trim a tad more on the hood, but went pretty easy. Installed the new modified gas pedal finally, and yep....had to mod the corner of the pedal surface a tad but this time it works...Installed my combo turn signal stalk/headlights/horn and got the wires ran over to the other side to terminate later....and started on a small sheet metal cover to cover an ugly spot on the side of the head. PICS:

Oof, I forgot to ask, theres a nine pin plug on the right fenderwell that has no terminus, has the green and black/yellow wires included...THEN, I found a rectangular 6 spade female plug on the lh side bottom of the dash with white/red, black/yellow, and two wires whose colors I can't remember (currently at work) just hanging out. Ever seen that? WTH does it do? LOL....ergggggg

Thanks! I'm chasing the c-5 plug too. I think a few pins might be corroded. This is maddening. The upside is I guess I can repair my dash. If you hear a large banging sound, its my head against the wall in my shop. 🙃

More often than not, the issue is poor grounds in the system. (Although that may not be your problem, as you've already tested, and failed, for +12V at the brake lamp switch.) Sounds like you may also already have the FSM; but if not, you can download it for free for all years at: https://www.xenonzcar.com/s30/fsm.html. (For your ease of reference, the stop lamp circuit is attached as a one-page pdf.) Hopefully I'm not giving you info you already have. 😜 Stop lamp circuit.pdf

This is how I feel watching some youtube channels. popularity doesn't mean skill or quality.

I've not checked the valve lash yet since the break in drive. The shop that had it said they did, but I think after the last 70 miles or so it wouldn't be bad to re-verify that everything is where it should be. Nothing wrong with triple checking, I'd really like my engine to last (and not trash my cam)!

Selling a pair of metal headlight cover frames (bezels) for an S30 Datsun (240z, 260z, or 280z).These are metal and were professionally done in triple chrome. They have a really nice mirror shine to them. Overall they look great, but I threw a picture in showing a minor flaw in the finish so you can see exactly what you're getting.Frames only, no clear lenses or seals included. Asking $350 obo Shipping available Email: Ion077940@gmail.com

I've been poring through the topics and I haven't seen my particular problem, so I'm going to forgo the mind-numbing search and ask here to see who has ideas. Issue; No power to black/yellow feed to switch, fuse box is live at that circuit (white/red-->black/yellow) but somewhere down the line it seems to have disappeared. Yes; green line in to hazard switch is hot, contacts do show continuity when tested (even the silly little green light lights up when the headlights are on), but when hazard is switched on, no flash, no power. I've got the dash out,and can see the junction box clearly. Fuse panel is unscrewed and is also visible. Thoughts?

Very nicely done, love it! I'm on my second early 260Z so I've got a soft spot for the S30 family middle child. I do have a syncrometer, I've been tuning sidedraft Webers on-and-off for close to 15 years now. It's been some time since I've played with SUs but they're pretty simple devices comparatively. BTW, have you checked your valve lash? This is super critical to do on a fresh head. The lash can change considerably and quickly over the first few hundred miles as the valves break into their seats. I did my motor break-in while driving the car to JCCS back in 2013 and by the time I reached SLO, a cam lobe was already wiped. My best guess is that it was a result of the aggressive wipe pattern of my cam combined with a rapid reduction in lash during break-in. I'd love to pop by Pre-Stage again some time as well, I've only been once and that was on a rainy day last December. Maybe I'll even have my side mirror repainted and fresh door cards mounted by then...

Hey Leon, Thanks for the reply! Pic attached for attention - you can probably figure out which are before vs after . The interior isn't all there yet, so not sharing that mess, still troubleshooting some stuff inside. Now that the alignment is done, I'm not opposed to bringing it down your way. Still working on break-in miles (it's at 78 total), so not trying to do any LONG drives just yet, but that might be manageable. Just have to figure out timing, and tooling. I don't have an empi style vacuum tester just yet, do you? I'll also be at Cars and Coffee (Vintage Oaks) and Pre-Stage (Marin Civic Center) in September, if anyone will be there! Robert

Thank you for the kind words. Im proud of this one and cant wait to get it dialed in a bit and get to enjoy it a bit on the street and track.

Such a clean, meticulous build...the car looks amazing. I'm really digging all the custom machine work you did, in designing and fabricating so many "one-off" parts & pieces. (I know several parts suppliers that would benefit from your level of skill and expertise.) 😜 Quite a feat to build a car at this level in such a short timeline. Great work!! 👍👍

08-19-2026 ATLAS Z UPDATE: I got my intake tubing back from the polisher today. I like it. PICS:

$170 is a lot less than I would have guessed for shipping something that size across the ocean. I've paid half that or more for shoebox-sized boxes from Japan.

Thanks guys, appreciate the comments, it was a ton of work, now it's on to the doors, hatch and hood next. I moved the car home into my garage, as I closed down my shop for good. Hope to keep making progress

Cool! I just sold my S2000 this year after 14 years of ownership and remember noting when I got it that it was dimensionally very similar to the Z. Length and height were nearly identical but the S2k was something like 4-6 inches wider!

Works great for me today! No issues and everything was quick to load.

Wow. This thread is the absolute epitome of "if you want it done right, do it yourself." BRAVO!

Hey Robert, sounds like a rad build! You should post some pics of what you're working with. I'm in Burlingame but also have three little kids so Novato is no-go. Unless you're able to bring the car down here in which case I'm happy to help! Otherwise, maybe reach out to the folks at ZONC (Z-Owners of Norcal) via their Facebook page to see if you get any action?

Got the the hood and inspection covers on. Happy