Coolant system overhaul 66 Barracuda

[1974DartSwinger]

Hey guys, I'm getting parts together to do an overhaul on my '66 Barracuda's coolant system. It's currently a 360 block/heads with 273 commando intake/carter AFB. Have the original 22" radiator that was re cored by previous owner. Been having annoying overheating issues leading to fuel perk, not wanting to start when hot, overheating in traffic - all the usual. I did a system flush, added overflow bottle. It runs fine but I still have to avoid traffic which can be hard at times. Adding a phenolic spacer under the carb with a couple gaskets did help but still not perfect. Time to do it right . . .

Scored one of the rare radiator shrouds but need to find the brackets to mount. Anyone making reproduction brackets or have a set to sell?

Would you guys consider just going with a different radiator all together? Is there one that drops in without cutting / drilling that would offer better cooling and shroud options?

Looking at pulling the factory water pump and going with a FlowKooler # 1701-3. Anyone have experience with this pump? Stick out too far?

The original fan is a 4 blade fixed - would it make sense to go with a 6 blade instead? Trying to avoid flex, considering fixed vs clutch.

Lastly, I'm leaning towards ditching the carter and going EFI with one of the FiTech systems - their Street 400 should be plenty for my needs. I think much of my fuel perk problems are related to the divorced choke with exhaust crossover dumping too much heat right under the carb. Will pull the carter AFB / original intake and go with one of the eddy air gap or similar options. I'm just ready for the easy button at this point; turn the key, drive and smile!

 

[cudamark]

How hot is it running? For sure, I would go with a stock 6 or 7 blade rigid fan. You lose a tiny bit of horsepower, but, they pull lots of air. The stock shroud will help a lot too. I'll check to see if I have any extra shroud brackets. They can be made too, but, not easily. Also make sure you have to hood to core support seal in good shape, as well as the bottom filler panel and it's seal.

 

[1974DartSwinger]

@cudamark - Thanks man! That'd be great if you had a set - I'd gladly take them off your hands just let me know. As for how hot, with a 160 T-stat it'll creep over 200 sitting and that's when I start to look for a side street or somewhere to get air flowing to cool her down. Only once did she puke her guts out but that was before the overflow bottle and on a car cruise night. The most annoying thing is anytime I stop for less than 30 min the thing doesn't want to start when it gets heat soaked and the fuel vapor locks.

Is there a easy to get aftermarket or reproduction 6/7 blade fan you'd recommend?

 

[dogbreath]

how long ago was it recored and has it always ran hot

 

[66fyssh]

I had temps of 210⁰ in traffic after swapping in a 5.9 with headers. Here's what solved my problems.

I'm using the factory A/C radiator and factory 7 blade direct drive fan. (i had the radiator hot tanked but the guy wouldn't rod it out for fear of damage. That was 12 years ago, lol). Air Gap intake and Edelbrock AVS2 carb with a wood fiber laminate 1/2" spacer. I kept the v-belt front end when I swapped to the 5.9.

No doubt in my mind that switching to the FlowKooler water pump made all the difference. In traffic on a 95⁰ day, the engine is right at 180⁰. It's almost unbelievable how much it helped me. Hopefully it will help you.

I'm not a fan of fuel injection...just heard too many horror stories.

You're on the right path, good luck!!

Edit: I got very lucky finding a factory shroud and 3 brackets. I made the 4th one. Maybe @RAT ROD AL or @cosgig Has one.

 

[cudamark]

@cudamark - Thanks man! That'd be great if you had a set - I'd gladly take them off your hands just let me know. As for how hot, with a 160 T-stat it'll creep over 200 sitting and that's when I start to look for a side street or somewhere to get air flowing to cool her down. Only once did she puke her guts out but that was before the overflow bottle and on a car cruise night. The most annoying thing is anytime I stop for less than 30 min the thing doesn't want to start when it gets heat soaked and the fuel vapor locks.

Is there a easy to get aftermarket or reproduction 6/7 blade fan you'd recommend?

200 isn't all that bad. Add the shroud and a better fan and you should be good. Sounds like an air flow issue. Usually holding the throttle wide open while cranking will clear the flooded problem. Make sure your heat riser is open when hot.

 

[RustyRatRod]

The stock style system is tough to beat. Upgrades like a high flow water pump and thermostat are smart choices for engines better than anything stock. I agree with the others regarding "some kind of" belt driven fan. I like the Mopar HP clutch fan if it will fit. They really move some air. The "hotter" you build the engine (pun intended) the more the need may arise for a better than stock radiator. Something with two large rows (1" - 1.5" tubes) should be plenty to cool a high compression hemi. If it's not, you got something wrong. Veering too far off the beaten path from stock usually results in trouble. I prefer sticking to to the stock type cooling system, but with well thought out upgrades.

 

[1974DartSwinger]

Thanks for the input guys, much appreciated! I'll give it a shot with the new pump from FlowKooler and install that fan shroud then see what happens.

@dogbreath Recore was about a decade ago now- It always ran hot if not moving. I'll bring out the thermal gun next chance and make sure there isn't a cold spot on the radiator that may be plugged just to be sure. I flushed the whole system 2-3 x and filled with fresh 50/50 (distilled) as well as water wetter. That with the overflow tank did help but still gets toasty. She's a happy fish going 55-60

@66fyssh Are you running a LA 360? How much of a difference did you really notice with that new pump? Mine has a block/heads from a 1974 360 - there's a couple different pump #'s but it looks like the #1700 is what I need. Thinking that eddy air gap would be a good call too since my 273 intake has the small ports going into the 360 heads. Did having that air gap seem to cool the carb down some too? I have a thick phenolic spacer at the moment which helped but not perfect. Hopefully just getting the motor cooler will help the fuel system enough to make a difference too.

Does anyone have a good part# for a compatible 6 or 7 blade rigid fan that's available new/reproduction or is it going to be an e-bay / swap meet deal? I believe its 17" to fit the factory shroud.

 

[66fyssh]

Are you running a LA 360? How much of a difference did you really notice with that new pump?

Mine is a 5.9 Magnum. Big difference with the FlowKooler pump!

 

[Bewy]

The pitch of the fan blades is important if you are wanting to reduce temps. You need a steep pitch.

 

[MadScientistMat]

Does it run hot while the car is moving? If it doesn't, I would focus on air flow as well as making sure the idle timing is correct.

 

[junkyardhero]

i'll throw another one down for the flowkooler pumps. they work, and they work well.

i like the stock V8 fixed fan, but a good clutch fan is a worthwhile investment if you have the room to fit it.

 

[66fs]

The radiator is not your problem if it runs cool while driving. Get a Chrysler flex fan, they pull lots of air at idle and change pitch when you rev it, I've used one with the Mopar part number 3462150. I don't run a shroud, but my radiators have 3 row cores. I have never had an AFB with vapor lock problems, but I've been running an electric fuel pump since the 70's. For exhaust I'm running Jet Hot coated 66 exhaust manifolds with no passenger side flapper valve and the HP single exhaust with 2 straight through mufflers in series.

 

[66Valiant528]

If winter driving isn't an issue you can block off the heat crossover passages with performance intake manifold gaskets.

 

[1974DartSwinger]

If winter driving isn't an issue you can block off the heat crossover passages with performance intake manifold gaskets.

Would this make the divorced choke stay on too long or not really an issue as the block/intake heats up? I'm not sure what temp those things need to open fully if the exhaust crossover is required or not. Good idea, I might just do that after checking the choke issue. Thanks!

 

[66Valiant528]

Would this make the divorced choke stay on too long or not really an issue as the block/intake heats up? I'm not sure what temp those things need to open fully if the exhaust crossover is required or not. Good idea, I might just do that after checking the choke issue. Thanks!

I can't say as I usually run an electric choke. I don't think it'll be an issue. Maybe someone else with a divorced choke set up can answer that. But a blocked heat cross over will help keep the intake and carb cooler. Some cross over plates have a small hole in them to allow some exhaust to pass through. Never used one. Maybe someone with a carbed Magnum head engine (which has no heat crossover) can say. A carb insulator would probably be a good addition as well.

 

[66fs]

Would this make the divorced choke stay on too long or not really an issue as the block/intake heats up? I'm not sure what temp those things need to open fully if the exhaust crossover is required or not. Good idea, I might just do that after checking the choke issue. Thanks!

What exhaust are you running?

 

[1974DartSwinger]

What exhaust are you running?

Just stock 360 manifolds into 2 1/2 duel

 

[66fs]

You probably just need a good fan. Does your passenger side exhaust manifold still have the flapper valve?

 

[AJ/FormS]

Just so you know
>The thermostat sets the minimum running temperature and has nothing to to with the max once it's open; Unless the doggone thing is too restrictive.
> rule of thumb is to, stopped and idling with the hood closed, to have about 30 degrees or more coolant temperature difference, from the hottest place on the stat-house (which can vary quite a bit), to the suction side of the pump, measured on the metal. If you get this, your rad is fine.

Here's my combo, built in 1999;
> I highly recommend a thermostatic clutch, and a 7 blade, hi-attack angle A/C fan on that clutch.
> I have been running a MINIMUM coolant temp of 205*F, since 2004 at least. The T-clutch keeps it no higher than 207*F, no matter how badly I am abusing it. I run a hi-flo pump and stat.
> My rad was an ancient POS, with patches on the patches, the day I installed it in 1999. It came out of a 1973 Dart318, with A/C. I installed it into the Slanty Core-Support, no mods, and with it's matching shroud.
> I run an Airgap intake and a Holly 750DP, NO spacer/just a gasket, and I cut a big hole in my hood, right above the airhorn, and sealed the carb to the underside of the hood.
> My headers are NOT wrapped.
> I have run three different cams in this 11/1 (PLUS) sweetheart, from a 292/292/108 to a 270/276/110, and now, a 276/286/110; all were hi-lifts running 1.6 arms. Most of the time, the cylinder pressure has been between 188 t0 195
> I have always run a manual trans, almost always with 3.55s, and a GVod since 2004.

> If your carb smokes up into the air cleaner shortly after shut-down, the carb is running too hot, and this may or may NOT be due to coolant temp; it could just be a leaky float-valve relaxing pressure in the supply line. A trapped air-pocket in that line, like in a fuel-filter, could aggravate that. Which is why I relocated mine to right close to the fueltank, on the suction side, and made a one-piece steel line from pump to carb, running up-hill continuously.

> People say (No finger-pointing here) that you need a lot of Idle-timing to prevent Idle-overheat. well, I have NOT found that to be true but, I do have alloy heads, which have several coats of orange paint on them.
>I run 12>14, at idle, but, My 360 will parade all day with just 5* Idle-advance.

> If your engine locks up and the starter will not crank it for say 20 minutes; My money is on the rings having swelled up and the end-gaps have become too tight .
Mine did this right from the start, and after a summer of chasing my tail, I pulled the engine, tore it down, and opened up the gaps/problem solved.
If it does NOT do that, then they're probably just fine.

> if you have a heated intake system, they tend to coke up over time, and then they trap heat right under your carb, which cooks the gas. Gasoline is made up of many different independent molecules. The lightest of them will evaporate at around 95*F. The heaviest will not dissociate until over 400. Your intake is normally at or near coolant temp. But when that passage cokes up, it's a lot hotter right under the carb. I made a lot of money in my younger years, chiseling out intakes.

Happy Hot-Rodding