I'm in the process of removing the old emissions equipment, and installing a weber. Before I reinstall the stock intake manifold I'd like to figure out how to reconnect the coolant hoses.

1. I have one hose from the drivers side, one from the passenger side, one from the pass side engine block, and the hose from the center coolant passage.

2. From what I've read many people retain the coolant passage between cylinder 2 & 3 due to the benefits of lower temps in the head. Is it worth keeping or should I just block this off?

3. I purchased the egr blockoff plate, and the plug kit for the manifold.

What is the proper way to connect these four hoses?

 

I would like to know as well. I'm looking to do this to my 78.

 

OK. I tried to upload pictures but my file is “too big”. I did the Weber 32/36 conversion from Weber Carbs Direct.
Based on your picture, the drivers side hose it a return line to the radiator. Leave that as is. On the intake side the hose coming from port between #2&3 goes to the passenger side firewall (yours looks ok. Don’t mess with it. The hose coming from the water pump tube is a return line. On your manifold you will have a nipple directing behind the carburetor between #3&4. Attach the water pump hose (yours is facing up) to the manifold nipple and you’re done. I’m guessing you had the water choke carb like mine. It’s very important to keep this loop in place or it can mess up your thermostat causing it to overheat. I’m not sure where the 4th hose is? If it’s from the carbon canister you can just leave it unhooked.

 

Not sure why I mentioned four hoses...

When I purchased my carb, I also pickup the intake manifold emission delete plugs and removed anything related to that system. I spoke with LCE and it looks like the best option is to buy the block off plate for that hose behind the waterpump since I went with the weber with electric choke.

I'll have a temp gauge installed so I can keep an eye on things when I'm on the road.

 

It’s your engine. Before blocking off that return line you should look at the coolant flow diagram for the 20R.
A quick explanation for why you want to keep that return line from the manifold to the water pump housing. Your intake manifold is filled with coolant. Hot coolant from the block fills the manifold until the thermostat opens and allows the hot coolant to return to the radiator to be cooled. The output from the block is directly adjacent to the thermostat housing in the intake manifold. What this means is all that super heated coolant in the back 2/3’s of the manifold cannot be cooled, so it will sit there and cook (if you’re lucky). The alternative is you develop an air bubble inside the manifold as the trapped ambient air has no means to escape. This could cause your thermostat to open late (not a good thing). Your temp sender is located at the thermostat housing. It’s telling you water temp is fine because it can’t sense the temperature at the rear of the manifold. Long term high heat is not good for gaskets or cast aluminum parts.

 

I'll take your advice and reattach the coolant hose to the manifold. One question I do have is where should I route the small outlet on this fitting? I'm assuming the line under the manifold will connect to this fitting to complete the loop, correct? Should I eliminate the smaller outlet on the fitting?

 

Add a length of heater hose to the nipple in your picture. Loop it up and around your accelerator linkage then attach to the long pipe that leads to the water pump housing (located under the manifold). This will complete the loop. The short stubby nub on the nipple can be capped off, or replace the entire nipple. I believe it’s a standard pipe thread (not in mm).