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Dadsun

Starting Carb Conversion: Flat Tops to Paltechs

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I'm in Louisiana. I would think if I were in Canada the coolant (heating) lines going through the manifold would be more important.  This other topic has several folks voting to keep the lines flowing, however, due to keeping temps from getting too uneven in spots.

 

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23 hours ago, Patcon said:

Maybe somebody else will confirm. I wouldn't think twice about deleting manifold heating

I can't tell if your pro or con on this. Doesn't matter but being a southerner that phrase could go either way. LOL

 

Edited by siteunseen
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I bought this replacement gasket from Z Car Depot. Is it recommended to use a gasket sealant on this?

IMG_20201219_151130.jpg

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2 hours ago, Dadsun said:

I bought this replacement gasket from Z Car Depot. Is it recommended to use a gasket sealant on this?

I recently installed a new manifold gasket and did not use sealant.  No issues experienced here.

 

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Getting very close to the finish line. 

I sometimes, on projects like these, wake up and think about things I've forgotten... Like whether the throttle linkage arm is the same length on both flat tops and round tops setups. Alas, they are not. :-(. Looks like my flat tops arm is an inch or two short for this project.

My options seem to be to (a) make an extension, or (b) keep looking for one. 

PXL_20210102_203948845.jpg

 

In the meantime, here are some pics....

 

PXL_20201229_001150138.jpg

PXL_20201228_203946338.jpg

Edited by Dadsun

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Right. When you switch to the 240 style balance tube, you'll find that your old shepherds hook is too short.

Not the most beautiful thing in the world, but you can cut your original in the middle-ish and weld on a piece of tubing to take up the gap. Here's one from a 74 260 as an example. I believe they changed the pivot mechanism that mounts to the firewall and the shepherds hook design between 73 and 74, so yours won't look like this. But the concept is the same:

Extendo mod used on a 74 that switched to a 240 balance tube:
P1130599.JPG

And here's a pic after the welding is done and cleaned up a little and installed. Note the newer design throttle linkage pivot on the firewall. Seen on the right side of this pic:

P1130600.JPG

So I don't know if the newer design pivot will bolt right up to your firewall, but if it does, you could switch to that and a longer shepherds hook from a 280 or ZX.

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Hmmm. Thanks. I was just assuming the way to go for a non-welder like myself would be to affix an extension of the eyes that receive the shepherds hook. 

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Many different ways to lengthen the linkage, so whatever works easiest for you.

If you take a good pic of the piece that mounts to the firewall, I'll snap one of the later version. If it looks like the new one will swap over as a bolt-up, I've got one here and a longer shepherds hook that I could part with. You could just bolt that in and go. I'll snap a pic of that if I get a chance and you're interested.

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Yes, interested. Thanks. Here are a couple of pics. It looks to me like the shaft is about 2" to 2.25" short on the new setup.

PXL_20210103_153215444.jpg

PXL_20210103_153233441.jpg

PXL_20210103_153759299.jpg

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Actually, the old flat top setup's receiving rod adds back the two inches. So, I'll insert that and should be stable enough to do the job. See pic:

 

PXL_20210104_000744639.jpg

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That old flat-top part should get you out of the woods for now. It really wants a bearing support closer to the end, but I think it should be OK for now.

So here's what I have. Question is... Will the pivoting mechanism mount to your firewall? Are the mounting holes in the same location(s)?
P1180174.JPG

P1180176.JPG

P1180179.JPG

 

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Wow,.that's nice. And yes, I'm wondering about the support on the carb side with that longer arm. Here is a picture of the underside. Looks like the middle hole is flipped, but the two outer holes line up. 

PXL_20210104_033130370.jpg

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If I get a chance, I'll take another pic today with a tape measure up against the bolt holes so you can see if it's the same as what you currently have.

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It looks like the newer design will bolt up. I'm kinda surprised.

Here's a pic of the dimensions on what I have:
P1180210.JPG

Send me a PM and we'll see if we can reach an agreeable agreement.    LOL

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Well, the carbs are on, no leaks, and it starts every time. Progress!

Now I need to tune them. I have a Uni-Syn tool that came with the car. I'm getting no air draw on the front carb, just the back. Is that normal?

I have a service manual and saw some old threads here on tuning/balancing, but if y'all have a go-to reference please pass along. 

PXL_20210113_215024637.jpg

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