Giving it one more go - 73 Charger Make Reliable/Driveable

[WH23G3G]

I'm going to give my 73 Charger one more go. It's still got a cooling problem, driveshaft problem, and maybe still vapor lock issues. It's been to several shops and hasn't been determined why temp gets too hot. It idles fine and drives ok but with all the traffic lights, stop signs, and general traffic in my area temp gets up real quick. I'm not in the country. It's got the 400-4bbl which I rebuilt probably 5-6 years ago with now only about 150 miles on it. It's a 76 block, .040, Sealed Power oem cam/lifters, new oem rockers, pushrods, shafts, springs, rebuilt 73 heads with new valves, Fel-Pro gaskets, Sealed Power rod and main bearings, milodon oil pump screen, melling hp oil pump. It's got a Weiand aluminum intake and an Edelbrock 1400 600 CFM carb. Not a dragster just want it as a cruiser. Factory a/c too. I found out the radiator I put in when doing all this was a 2 row. It was new but only a 2 row and it measured 27 1/4" with a factory 28" shroud made to fit. It originally had a 318 and 26" radiator which I can't figure out fit squarely since one side of the core support is flared out and the other side is flat. But I couldn't find a perfect match radiator for a big block so this was the closest and it maybe a problem. I think originals were 3 or 4 row. I see they offer 26" 3 core aluminum ones but don't know how well they fit. My radiator shop said they could add a core or maybe 2 if I bring the radiator to them but don't know if it will be more than an aftermarket 26" aluminum 3 core. If I can kill the cooling issue will that help with vapor lock too? I did put the recommended spacer Edelbrock told me to get and replaced the fuel pump. If I can't figure out who can fix it or if I can't fix it myself unfortunately I will have to sell. So any suggestions on radiator choices? Get the aluminum or try and have more cores added to this one?

[RallyeMike]

Original radiators were two row. 28 inch wide was the max width stock. This covered big block with AC. You should be good.

I assume you have verified that your thermostat is opening correctly. Remove it for a trial and see if that changes anything.

Do you have a clutch on your fan? When worn, it can look like and feel like its spinning and moving air, but its not enough to cool the car at low speeds no matter how good a radiator you have.

[JR]

What kind of fan are you running? I would highly recommend a thermal-clutch fan. They are very efficient at moving large amounts of air.

Double-check your engine timing. Too much will cause it to run hot at idle and in traffic.

Also, are you running a fuel return line, or a single feed line?
A return line helps with vapor lock BIG time. Along with routing fuel lines away from heat sources, and making heat shields if necessary.

A very basic question here, but is the coolant a 50/50 mix? It should be.

Ceramic coating the exhaust headers makes a big improvement also. Bare steel headers throw off huge amounts of heat that radiates around the engine bay, heating things up.

Also, where do you live? If you're driving stop and go in the Arizona desert, that would be less alarming than if you live in the milder Pacific Northwest.

[flyinlow]

So, going down the highway burning 5 gallons of fuel per hour your engine temp is normal. But , sitting at a traffic light burning 1 gallon(or less) per hour it overheats.  The part of Your cooling system  that makes air go thru the coolant to atmosphere heat exchanger  at slow vehicle speed  needs some work

Bad fan clutch, missing or ineffective shroud, wrong fan, wrong water pump pulley would be the places I would look.