Fixed cooling fans for a 340

[nutz]

Stock 340 fan is the 215 clutch fan, same as 426 Hemi. 7 blade 18” with 2.25” pitch.

If you don’t care about factory correct, just factory specs the GM 772 fan is what I used on my Duster 340. A link to the reproduction fan I purchased and have been running over a year no issue.

Camaro Chevelle 69 70 Nova Impala 772 Engine Fan 7-Blade dated C69 3947772 | eBay

Just the word hemi on it sounds expensive...

 

[Newbomb Turk]

Not necessarily looking for max cooling effect from just the fan, more of a max cooling effect for the entire system especially while idling during a show or cruise. Currently I have the MP 5 blade with Hayden clutch which is fine for all driving conditions except it gets pretty hot during extended idle and cruising during shows. It’s mostly a show car so I am hoping to get more air at slow speeds.

That’s not a fan problem.

There’s many threads on this forum about this issue so I’m not typing it out again but you can search for it.

It ain’t the fan that’s the issue.

 

[Kenflo]

That’s not a fan problem.

There’s many threads on this forum about this issue so I’m not typing it out again but you can search for it.

It ain’t the fan that’s the issue.

Low airflow through the rad during parade cruising and extended idle time like not moving at all is what I believe is the problem, I could be wrong but I am willing to do a fan swap to see if it helps. Car runs great in all other conditions. I’m not 100% convinced that the 5 blade fan with Hayden HD short clutch is the best fan for my combo especially during those conditions.

 

[Newbomb Turk]

Low airflow through the rad during parade cruising and extended idle time like not moving at all is what I believe is the problem, I could be wrong but I am willing to do a fan swap to see if it helps. Car runs great in all other conditions. I’m not 100% convinced that the 5 blade fan with Hayden HD short clutch is the best fan for my combo especially during those conditions.

Read this post you made again. You know what the issue is. My point is your fix isn't a fix.

Screw it. I'll type it out again.

You have an air flow AND a coolant flow issue. A fan change won't move the needle.

You need to look at your pulley sizing first. The water pump and the crank need to be turning the same speed (1:1) at least. If it's not 1:1 you need to correct that first.

If you are under driven, which I suspect you are the fan and the water pump are turning less than crank speed.

Like I said, you can change the fan to anything you want, but if the pump and the fan are turning too slow it won't matter.

 

[junkyardhero]

Read this post you made again. You know what the issue is. My point is your fix isn't a fix.

Screw it. I'll type it out again.

You have an air flow AND a coolant flow issue. A fan change won't move the needle.

You need to look at your pulley sizing first. The water pump and the crank need to be turning the same speed (1:1) at least. If it's not 1:1 you need to correct that first.

If you are under driven, which I suspect you are the fan and the water pump are turning less than crank speed.

Like I said, you can change the fan to anything you want, but if the pump and the fan are turning too slow it won't matter.

Thermostat is 180, water pump is the high volume Milodon, pulleys recently changed to a 1:2 ratio overdriven. Driving around normally runs great between say 170-190, when cruising slowly for like 20 or so mins it will creep up to 210-220 and will puke a bit into the recovery tank

 

[Newbomb Turk]

At 20% over if it’s still overheating at idle and low speeds he needs to look at his radiator.

It damn sure isn’t a fan problem

 

[nutz]

Easy test on fan is when idling put a big box fan in front of it if it cools fan problem
If not like the guy says pump
Increase rpms then and see if it's cooling off

 

[Wvbuzzmaster]

To everyone that keeps telling this guy the fan isn’t the problem and changing it won’t help, you guys are not correct. From what I learned 1.5 years ago when I went thru a similar question (7 blade fixed vs 6 blade clutch) my end result was to skip using the 6 blade and measure pitch… The new to me 6 blade was not a major improvement in pitch to the 1.5” pitch 7 blade (slant 6 fan). I looked in factory service manual and it said 340 cars were equipped with 7 blade 2.25” pitch, and I opted to go to a factory spec 7 blade fan (even though it was a cheaper GM 772 with same specs).

Kenflo has a performance engine and the 5 blade fans were not standard on performance engine options. Were they on 318s and 360s, yes, but those were not considered the performance engine option (360 guys might argue but they were detuned compared to a 340 back in the 70s). So the best course is to trust your gut and swap the fan to a 7 blade 2.25” pitch 18” fan. It’s also the least intrusive option, everything else is taking the engine apart…