Starting Carb Conversion: Flat Tops to Paltechs

[siteunseen]

I plugged mine off. Car runs great. The carbs are cool to the touch now. The thing is most of those thermostats fail to close up when heated allowing the hot coolant to run through constantly. Plus you remove potential leak spots. That 90 degree hose at the rear of the head is suspect #1.

[Dadsun]

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.

 

[siteunseen]

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.

 

Edited December 13, 2020 by siteunseen

[Dadsun]

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

[DatsunZGuy]

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.

 

[7tooZ]

45 minutes ago, DatsunZGuy said:

 

I agree

[Dadsun]

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. 

 

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

 

Edited January 3, 2021 by Dadsun

[Captain Obvious]

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:

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:

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.

[Dadsun]

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. 

[Captain Obvious]

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.

[Dadsun]

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.

[Dadsun]

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: