340 cooling

[Demonx2]

FWIW...

My 71 Demon 340 ran hotter than I wanted. It would run roughly 180-190 down the road and creep upwards of 205 at idle, even with a 160 tstat.

.030 "stock" rebuild of the 340. It has the old "hemi grind" purple cam in it but is otherwise stock.

So I bit the bullet and got a 22" correct p/n Glen-Ray rad for it. Buy once, cry once! I installed it in September and the car since runs pretty darn close to stat temp all the time here in Florida. 160-170-ish most of the time. Not sure I've seen more than 175 ever with it. One thing for certain is it runs much cooler now than previously. I use a Hayden standard length clutch and a 7-blade fan with the correct rad shroud. Fan is darn close to 1/2 in and 1/2 out of shroud.

We'll see what next summer brings but I'm very confident it will be MUCH cooler than before and meet my expectations.

 

[mad dog]

Demonx2...very nice!!!
im pretty confident in my newly re-cored radiator and shroud, its the other cooling components i want to get right during assembly..

 

[RustyRatRod]

If it’s a factory 340 car is should have a 26 inch radiator.

Not in a 68 A body.

 

[Newbomb Turk]

must have been owner added.

not in the 72 parts book

View attachment 1716355370

I’m 100% sure it was 100% unmolested. The previous owner never touched it.

It came through with 2.02 valves, 10.5:1 pistons and a steel crank.

I didn’t realize at the time that car would have dominated in Stock Eliminator.

It would have run two classes lower with the 1.88 valve and 8.5:1 compression cars.

Every number on that car matched.

 

[Newbomb Turk]

Not in a 68 A body.

Yeah, I’m not 100% sure those books are 100% accurate.

I was talking to my brother a minute ago and we know his 69 Dart had a 26 inch radiator in it. And that car was unmolested. That we know.

I’m going to do some more checking, but it’s funny how we used to make fun of the Chevy garbage that was always over heating, and the Chryslers always had a bigger radiator.

Come to think of it, my buddy bought a 71 Demon with a 318. That had a 26 inch radiator in it, but I think the first owner ordered it with a big radiator in it.

 

[RustyRatRod]

Yeah, I’m not 100% sure those books are 100% accurate.

I was talking to my brother a minute ago and we know his 69 Dart had a 26 inch radiator in it. And that car was unmolested. That we know.

I’m going to do some more checking, but it’s funny how we used to make fun of the Chevy garbage that was always over heating, and the Chryslers always had a bigger radiator.

Come to think of it, my buddy bought a 71 Demon with a 318. That had a 26 inch radiator in it, but I think the first owner ordered it with a big radiator in it.

Yall bees crazy. That we know.

 

[mad dog]

thread got derailed... thanks to those that gave good advice

 

[Newbomb Turk]

thread got derailed... thanks to those that gave good advice

It didn’t derail. If you only have a 22 inch radiator I’d upgrade to a 26 incher.

 

[Newbomb Turk]

Yall bees crazy. That we know.

We all know my wife would swear to that in court.

But she loves me (so she says).

 

[RustyRatRod]

But she loves me (so she says).

Ain't no accountin for taste.

 

[Newbomb Turk]

Ain't no accountin for taste.

lol true dat!!!

 

[autoxcuda]

It didn’t derail. If you only have a 22 inch radiator I’d upgrade to a 26 incher.

If you have a pre-73 A-body and you want a 26” radiator, make sure to cut the radiator support opening to so that radiator core is not blocked by the radiator support.

 

[crackedback]

Yeah, I’m not 100% sure those books are 100% accurate.

I was talking to my brother a minute ago and we know his 69 Dart had a 26 inch radiator in it. And that car was unmolested. That we know.

I’m going to do some more checking, but it’s funny how we used to make fun of the Chevy garbage that was always over heating, and the Chryslers always had a bigger radiator.

Come to think of it, my buddy bought a 71 Demon with a 318. That had a 26 inch radiator in it, but I think the first owner ordered it with a big radiator in it.

Someone put a 26" in after it left the factory. The radiator support/opening and attaching points are 22 and 19 inch only for pre 73 cars.

AC 340 cars got a 22" in 1972

 

[Newbomb Turk]

Someone put a 26" in after it left the factory. The radiator support/opening and attaching points are 22 and 19 inch only for pre 73 cars.

AC 340 cars got a 22" in 1972

I’m 100% sure it was never touched. I was the second owner.

No one cut up anything on that car.

 

[davescuda]

Just run your stock **** and set your base and total timing and you will have no issue. Let’s not get crazy here.

 

[autoxcuda]

I’m 100% sure it was never touched. I was the second owner.

No one cut up anything on that car.

Maybe measuring different. Like mounting bolt across to mounting bolt.

Still have the car, go measure the opening. Or measure the abody you have now.

 

[Newbomb Turk]

Maybe measuring different. Like mounting bolt across to mounting bolt.

Still have the car, go measure the opening. Or measure the abody you have now.

That car is long gone. I know what it had.

That car wasn’t supposed to have 2.02 valves, the high compression pistons or the steel crank, but it had them.

 

[davescuda]

This post went to ****

 

[junkyardhero]

the folklore of the special 1 off skunk works built demon with a 26" radiator. so rare we're talking "Black Ghost" territory over here.

hushed and reverent tones, boys. keep your voices low and full of respect.

 

[Newbomb Turk]

the folklore of the special 1 off skunk works built demon with a 26" radiator. so rare we're talking "Black Ghost" territory over here.

hushed and reverent tones, boys. keep your voices low and full of respect.

No folklore.

 

[Newbomb Turk]

This post went to ****

How so? The OP got his advice and the discussion is about radiator size.

Relax.

 

[Professor Fate]

That car is long gone. I know what it had.

That car wasn’t supposed to have 2.02 valves, the high compression pistons or the steel crank, but it had them.

No surprise there. The low compression cast crank 340 didn't hit the assembly lines until late in the '72 model year. Majority of the production run was high compression forged crank motors.

 

[junkyardhero]

No folklore.

if you say so.

 

[RustyRatRod]

No surprise there. The low compression cast crank 340 didn't hit the assembly lines until late in the '72 model year. Majority of the production run was high compression forged crank motors.

Yeah I think the changeover was April of 72 from what I've gathered.

 

[Newbomb Turk]

if you say so.

I do.