1978 Carb with 1973 Distributor Help

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Apr 14, 2011
Huntsville, TX
Ok, I've searched a lot, and haven't found my answer yet. Another guy had the exact opposite problem, a '73 carb with a '78 distributor. So let me first reveal what a few weeks of searching has taught me. It is a 1978 FJ40 produced 10/77. The body and frame serials match. The block is a service replacement, only stamped "2F" where the serial number should be, and has a cast date of "00405", which I take to be April 5, 1980. The carb is stamped something like J77 (I can't remember it verbatim right now) which I take to be a production date of 10/77, which should make it the original carburetor. The plate on the distributor reads 19100-60064 and 029100-2030 which I believe makes it a 1973 vacuum retard model. It has been Bubba desmogged. Basically any funny lookin box with vacuum hoses was cut out. Yeah, I didn't do it, that's just one of the headaches I have inherited from the PO; you should see what he did to the front springs in my "I joined the forum" thread. Anyway, on to a question. The vacuum biscuit on the distributor is currently connected to the vacuum port on the carburetor that is just below and to the left of the air mixture screw on the valve cover side. Is that right? I don't believe so. If I can wrap my brain around vacuum retard, it seems like it should be a strong source of vacuum at idle that goes away upon acceleration, and when setting the timing this vacuum source should be connected. What port would be suitable for this task? I don't have a picture right now, I'm at work, so I'll get that up tomorrow if it is needed. Thanks in advance for any replies.
The optimum way to use a vacuum retard distributor is as a door stop!

The second most optimum way to use a retard distributor is with the retard disconnected.

The third most optimum way is to hook the retard diaphram up to a ported vacuum source on the secondary side of the carburetor. I would ONLY do this if you had a motor that was actually pinging with predetonation under load with the secondaries open, as that is the only time retard would actually be useful.

If this isn't in the FAQ, it should be.


Mark A.
Thanks Mark, I've read lots of your posts and some of your website and glad you chimed in here. I'll double check FAQ section to be sure. Wish I just had a '78 distributor to put in place of the '73. For now I will just run the '73 without vacuum and see how it goes. Hopefully I will have front springs back under it this weekend with the shackles on the front as Toyota intended LOL
Let's dust off this old thread for an update shall we? Back in 2011 I followed Mark's advise and disconnected vacuum to the retard distributor, and went on my merry way. Fast forward to 2020 and now I want to get my 40 road legal. So, I called up Mark @65swb45 and ordered 19100-61180 Toyota distributor with Pertronix igniter already installed and ready to go. Easy transaction and fast shipping, thank you sir! I haven't installed it yet because I'm slow... and also have to get the engine back in the engine bay, but here are some pictures:

Side by Side

And to go ahead and follow advise to the letter:


It's strange reading my old threads and seeing how much I didn't know then that I do know now. I guess 9 years of reading build threads and random questions in the 40 section starts to rub off on you LOL.
In my infinite wisdom 20 years ago I chucked out my OEM dizzy and threw a Mallory on it. Smart right? Whatever.
Fast forward, the 40 is now my son’s [MENTION=1441]Plantman[/MENTION] the dizzy is eating itself (full of metal shavings, that’s bad, right?) and he’s working on solutions.
I’m curious to see if you find any performance difference from that old retarded dizzy to this new one. Obviously with the pertronix it’ll require less maintenance.
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Good timing on your reply, I got the engine running again the weekend before last! :) I don't know if I have a good comment on performance on this new distributor vs the old one, for two reasons. First, I almost got the transmission in yesterday... almost. So not doing a whole lot of moving yet. Second, with the old one I was never street legal, so most of what I was doing was just driving through the woods on old logging trails, not even near any mud holes either. But I do already have a positive observation to make; I followed the FSM on stabbing the new distributor, and then pumped the gas pedal twice and turned the key.... It was instantly purring! I was so surprised I didn't know what to do next, I was expecting some fires and misses etc., but there was none of that. I swooped in with my timing light and the timing was right around 7* before TDC. This fancy new light I have has the dial on it, so I cranked it to 12, turned the distributor a tad bit more until the light was on the TDC mark, and tightened the hold-down clamp. Done. Easiest time I have ever had at setting the timing, and this ain't my first rodeo LOL. Since then, I did the 20 minute run-in on breaking in a new camshaft that I have read about, I think I did okay. I'm using Lucas 10w30 break-in oil, so the ZDDP is in there. And since then, I've had it up to operating temperature several times, fixing a few little things that popped up along the way. It does run super smooth, much better than before. That being said, there are new valves, rings, bearings, coil, wires, etc. etc. I've been pretty thorough with it. Overall, when I was trying to think about replacing the old distributor, the OEM Toyota won out over the other options for me for a few reasons: OEM isn't going to be available forever, so I wanted to get while the getting was good, and I've fought with an HEI distributor on an '86 Chevy pickup, that wouldn't run right anytime there was moisture in the air. That coil in the cap would just play out, not real sure what was going on, but I didn't want to see one of those under my hood again LOL. I hope some of my rambling helps you with your decision!

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