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1967 Camaro RS/SS, 383 cu. in., 5-speed Tremec, 3:73 Posi.
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Discussion Starter · #1 ·
I have a 1967 Camaro RS/SS, 383 stroker, AC, manual tranny, Be Cool radiator. 23" shroud (3893814), short water pump and need some advice on choosing a fan. I live in Texas and the summers can get hot, when driving the temp. is good, if it sits at idle for awhile the temp. will get up and over 220 degrees, timing, carb., radiator are in great shape and the current fan sits half in half out of the shroud. I am changing from the fixed fan to a clutch fan. I am going to purchase the Hayden 2747 fan clutch, important areas to note is the fan bolt circle pattern which is 3.25", the mounting diameter for a fan is 2.59". I have narrowed my fan choice down to the Goodmark GMK4012312681 and the Dynacorn M1017. I believe both fans will fit the Hayden fan clutch 2747.
Hopefully, my fellow enthusiast can help me chose a good fan. Has anyone had experience with either of the two fans I mentioned or any other fan that fits the Hayden 2747 fan clutch and can offer any positive/negative advice? Classic Industries fan 3947772 is great but the fan bolt pattern is 3.0" and I need a bolt pattern of 3.25" Any help and advice is greatly appreciated, Thank you.
 

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68 Base Camaro, 355 Offy crossram, Richmond Street close ratio 5 spd, 92K SoCal car
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Hello This is what I run on my 355 swp 3 core GM 68 Camaro. TX2 GM 7 blade fan with 3.25 bolt pattern. My TX2 has the full length square blade ends unlike other that have the ends clipped on an angle. Fan sits half in/half out of shroud likecit should.

I lived south of Tucson for a brief time and the car idled, drove in city, drove down interstate without ever getting over 190 on 115 degree days. Gates 190 T-stat, 64-68 SHP GM curved cast iron T-stat housing that helps also. Aluminum high volume water pump with billet cnc impeller, both bypasses (intake to wp & wp to block on passenger side leg of pump mounting surface) are plugged off. Clutch is from Autozone listed for 68 302 & 396/375 hp solid lifter cars, clutch stays engaged a little longer than the other clutches. Clutch comes with a bushing if your current pump may have the smaller diameter mounting dowel.

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I am a firm believer of buying high quality parts and that often requires spending more. But I also believe there are a lot of hidden quality parts that don't break the bank and perform just as well, sometimes better. So fair to say I don't throw $$ blindly at parts or system when there is no benefit. Also it's important to look at the complete system.

I am also sure my Richmond close ratio 5 speed w/o OD, 5th is 1:1, allows me to run 2.73:1 rear gears to cruise the AZ highway & use gears 1-4 in town matching identically a Muncie cr car with 4.11:1 gears (4th is still 1.5:1). Have your cake & eat it to. This low numerical 5th gear reduces cruise rpm 34% keeping it cool in 112-118 days I had car out in AZ.

A lot of ways to build a cooling system. This does everything I need it to do and didn't kill my budget.
 

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I have a 1967 Camaro RS/SS, 383 stroker, AC, manual tranny, Be Cool radiator. 23" shroud (3893814), short water pump and need some advice on choosing a fan. I live in Texas and the summers can get hot, when driving the temp. is good, if it sits at idle for awhile the temp. will get up and over 220 degrees, timing, carb., radiator are in great shape and the current fan sits half in half out of the shroud. I am changing from the fixed fan to a clutch fan. I am going to purchase the Hayden 2747 fan clutch, important areas to note is the fan bolt circle pattern which is 3.25", the mounting diameter for a fan is 2.59". I have narrowed my fan choice down to the Goodmark GMK4012312681 and the Dynacorn M1017. I believe both fans will fit the Hayden fan clutch 2747.
Hopefully, my fellow enthusiast can help me chose a good fan. Has anyone had experience with either of the two fans I mentioned or any other fan that fits the Hayden 2747 fan clutch and can offer any positive/negative advice? Classic Industries fan 3947772 is great but the fan bolt pattern is 3.0" and I need a bolt pattern of 3.25" Any help and advice is greatly appreciated, Thank you.
This is what I have
Maradyne MM22K
 

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1967 Camaro RS/SS, 383 cu. in., 5-speed Tremec, 3:73 Posi.
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10 Posts
Discussion Starter · #6 ·
Hello This is what I run on my 355 swp 3 core GM 68 Camaro. TX2 GM 7 blade fan with 3.25 bolt pattern. My TX2 has the full length square blade ends unlike other that have the ends clipped on an angle. Fan sits half in/half out of shroud likecit should.

I lived south of Tucson for a brief time and the car idled, drove in city, drove down interstate without ever getting over 190 on 115 degree days. Gates 190 T-stat, 64-68 SHP GM curved cast iron T-stat housing that helps also. Aluminum high volume water pump with billet cnc impeller, both bypasses (intake to wp & wp to block on passenger side leg of pump mounting surface) are plugged off. Clutch is from Autozone listed for 68 302 & 396/375 hp solid lifter cars, clutch stays engaged a little longer than the other clutches. Clutch comes with a bushing if your current pump may have the smaller diameter mounting dowel.

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I am a firm believer of buying high quality parts and that often requires spending more. But I also believe there are a lot of hidden quality parts that don't break the bank and perform just as well, sometimes better. So fair to say I don't throw $$ blindly at parts or system when there is no benefit. Also it's important to look at the complete system.

I am also sure my Richmond close ratio 5 speed w/o OD, 5th is 1:1, allows me to run 2.73:1 rear gears to cruise the AZ highway & use gears 1-4 in town matching identically a Muncie cr car with 4.11:1 gears (4th is still 1.5:1). Have your cake & eat it to. This low numerical 5th gear reduces cruise rpm 34% keeping it cool in 112-118 days I had car out in AZ.

A lot of ways to build a cooling system. This does everything I need it to do and didn't kill my budget.
Hey SY1, I have to say it looks like you have nailed it, really great pictures, helps a lot. I tried to find a TX2 fan and was not successful, I heard back from Summit today and they confirmed the Hayden 2747 fan clutch and the K193 fan will fit one another which I believe I will buy. I compared your fan clutch pictures to the Hayden 2747 and they appear to be identical, I also compared your TX2 fan to the K193 and they are very close in appearance, I like the squared off blade ends. I am like you, I do not mind spending the money on quality parts as long as they work. I am not into aesthetics, what matters to me is function. Again, thank you very much for the great pictures, identifying the parts and sharing your set up, it is appreciated.
 

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Not sure what the TX2 blade is, but it looks just like the GM 7 blade #772 and is what you want. See how much angle pitch is in those blades to move the air.
The Hayden HD 2747 clutch and the 772 blade was the only thing that solved my overheating.
 

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68 Base Camaro, 355 Offy crossram, Richmond Street close ratio 5 spd, 92K SoCal car
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The 772 seems to be a solid & popular choice, can't go wrong with it. I run the TX2 bc it was on the car when I bought it and my time in AZ proved to me no need to fix what isn't broke. Had I been looking for a fan the 772 would have been my choice too.

From what I have see online TX2 keeps coming up as C3 Corvette 350 w/AC. Would make sense. Most TX2 stamped fans I see online look different with curved or clipped corner blades . Did see one like mine but it is polished. Derale makes nice stuff also as Just1More suggested.

I don't want to get into the electric vs mechanical debate, someone got a little excited last time. Both systems can be made to work in extreme heat. Both require careful selection of high quality components. Both should be explored. Consider how your car is used. Consider the cost of starting from scratch vs upgrading a component or 2 to the system you have. Consider your budget. Everyone has different desires, tastes, budgets, dreams. If there was only one way to build a car it would get boring really fast. ;)
 

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68 Base Camaro, 355 Offy crossram, Richmond Street close ratio 5 spd, 92K SoCal car
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CAMMAN that K193 fan looks just like it'll work great. Did someone confirm 2747 fits the bolt pattern on the K193 and your water pump? Reason I ask is Summit ad recommends 2705 Hayden with K193, but answered a question saying 2747 will work. Also 2747 shows dual pattern mounting base at water pump and the next 2 pics show 4 slotted holes. I think either will work in both style pumps. But I would ask Summit if the K193 bolt pattern is 3 or 3.25" and if it is 3.25 then the 2747 you are buying does look more correct. I wish Summit had listed these bits of important info in the specs.
 

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1967 Camaro RS/SS, 383 cu. in., 5-speed Tremec, 3:73 Posi.
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10 Posts
Discussion Starter · #11 ·
CAMMAN that K193 fan looks just like it'll work great. Did someone confirm 2747 fits the bolt pattern on the K193 and your water pump? Reason I ask is Summit ad recommends 2705 Hayden with K193, but answered a question saying 2747 will work. Also 2747 shows dual pattern mounting base at water pump and the next 2 pics show 4 slotted holes. I think either will work in both style pumps. But I would ask Summit if the K193 bolt pattern is 3 or 3.25" and if it is 3.25 then the 2747 you are buying does look more correct. I wish Summit had listed these bits of important info in the specs.

Yes, Summit did state the K193 and the 2747 will bolt together. In the Classic Ind. catalog it states the K193 replaces the 772. I did a lot of checking the spec's of various fans and I found the 772 bolt pattern is 3.0" and the center hole 2 3/8", the K193 bolt pattern is 3.1/4" and the center hole is 2 1/2". My best guess is it has to do with 1967/68 Camaro was the 772 fan, 1969 and later years the change was made to K193. The hub on my Edelbrock water pump has bolt hole spacing for either a 1 3/4" or 2 1/8". I had a heck of a time trying to get the spec's on fans from any supplier, they list the parts as if everyone has original equipment because a supplier would say, well, it fits your year vehicle so I am sure it will work. It gets very frustrating, I triple check everything so when parts I have ordered will be correct. To me, the critical information such as 1. fan bolt pattern, 2. fan clutch bolt pattern for the fan, 3. water pump bolt pattern, 4. pilot hole diameter, 5. center hole dimension, 6. and the mounting plate to edge of clutch dimension. Speaking for me if these spec's were included in the fan and fan clutch listing it would help to eliminate calling and/or emailing to ask for the spec's. To top it off I actually had been told, "sorry, we don't have that information available or the information was not supplied to them. One other bit of information regarding the Hayden fan clutch, the 2705, 2747, 2947, 2797. The 2705 is non-thermal, 2747 and 2947 are thermal, heavy duty and identical with the exception of the 2947 is shorter, and I think 2797 is a severe duty fan clutch, I believe all have 4 slotted holes for mounting to the water pump, cheaper to make with slots than 4-8 holes that require drilling and tapping. Sorry, I rattled on, I have a tendency to put out to much information. Again, thanks to everyone for their input.
 

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68 Base Camaro, 355 Offy crossram, Richmond Street close ratio 5 spd, 92K SoCal car
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1967 CAMMAN no problem and I appreciate your info, I do the same thing when I post for the same reason, it helps other avoid the issues that aren't often mentioned when taking on a project. Huge help if it can save someone the trouble of returning parts, $$, and the troubles of learning those hidden details.

As bad as Summit Racing sight is for lack of details Jegs is far worse and Jegs will sell you parts they don't have, charge your card and tell you days later they are out of stock and ship date is unknown. That's when I go to Speedway Motors or back to Summit and Jegs refunds my $$. The local parts stores are useless for most items, but do get lucky every now & then.

As you know niw the sbc water pump, clutch, fan and even pulleys compatibility gets over complicated quickly. One last thing I had to do was buy spacers for between my crank pulkey & balancer and another between water pump and pulley to perfectly align all the pulleys. They come in kits of varying thicknesses. Glad to hear you got what you nedded and I am adding the clutch info to my notebook! ;)
 

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1967 Camaro RS/SS, 383 cu. in., 5-speed Tremec, 3:73 Posi.
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Discussion Starter · #13 ·
Hey Everyone,
I received the Hayden 2747 fan clutch and the K193 fan and I wanted to share my findings. I ordered the parts from Summit and the fan and fan clutch shipped out of Sparks, NV in a carton big enough to hold a washing machine and not one piece of packing material to stop the items from taking a pounding during shipment. The box the fan was in had CHL Auto Parts all over it but of interest was the two different labels on the box, one label on the front stated a K193 fan and on the side of the box another label stating it was a GMK-4012312681 fan. When you compare the two part numbers on line the fans look identical as well as having the same specifications. If anyone has a question about the K193 fan and/or Hayden fan clutch let me know, the first thing I did was to verify the two fit together and the fit was very good. Then I brought out my calipers and micrometer and wrote down every conceivable dimension on the two for future reference.
As it turns out the 18" fan is to big only because of the poor installation of the BeCool radiator and fan shroud from a previous owner, I will leave it as is temporarily so I can pay attention to mounting a fan and fan clutch. I purchased a Derale 17" fan P/N 17117 to mount on the Hayden fan clutch. While I was reviewing my options for a 17" fan I came across some useful information concerning all Derale fans that are used with a fan clutch for clockwise rotation and I thought quite ingenious on behalf of Derale. Derale has a 17", 18", 19" and 20" fan clutch fans and with the exception of the diameter the rest of the specifications are identical, Flange bolt circle: 3" / 3 1/4", Flange diameter: 2 3/8" / 2 5/8", Mounting surface to front: 1", Mounting surface to back: 1", Depth: 2", Blade pitch: 27 degrees, Rotation: Standard (Clockwise). It appears the only change in manufacturing these four fans is the blade length.

I apologize in advance for boring some of you with tedious information but for those of you that have experienced how difficult and frustrating it is trying to find out the specifications on fan clutch fans and fan clutches I hope you may find this information helpful.
In closing I would like to add, in my search for fan clutch fans and fan clutches I emailed the various suppliers and stated how critical the specifications are when trying to purchase these items and knowing they will marry together because the information is stated clearly allowing you to make a selection without a dozen phone calls and emails. The lack of information on these products is uncalled for, just my opinion.
 

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Hey Everyone,
I received the Hayden 2747 fan clutch and the K193 fan and I wanted to share my findings. I ordered the parts from Summit and the fan and fan clutch shipped out of Sparks, NV in a carton big enough to hold a washing machine and not one piece of packing material to stop the items from taking a pounding during shipment. The box the fan was in had CHL Auto Parts all over it but of interest was the two different labels on the box, one label on the front stated a K193 fan and on the side of the box another label stating it was a GMK-4012312681 fan. When you compare the two part numbers on line the fans look identical as well as having the same specifications. If anyone has a question about the K193 fan and/or Hayden fan clutch let me know, the first thing I did was to verify the two fit together and the fit was very good. Then I brought out my calipers and micrometer and wrote down every conceivable dimension on the two for future reference.
As it turns out the 18" fan is to big only because of the poor installation of the BeCool radiator and fan shroud from a previous owner, I will leave it as is temporarily so I can pay attention to mounting a fan and fan clutch. I purchased a Derale 17" fan P/N 17117 to mount on the Hayden fan clutch. While I was reviewing my options for a 17" fan I came across some useful information concerning all Derale fans that are used with a fan clutch for clockwise rotation and I thought quite ingenious on behalf of Derale. Derale has a 17", 18", 19" and 20" fan clutch fans and with the exception of the diameter the rest of the specifications are identical, Flange bolt circle: 3" / 3 1/4", Flange diameter: 2 3/8" / 2 5/8", Mounting surface to front: 1", Mounting surface to back: 1", Depth: 2", Blade pitch: 27 degrees, Rotation: Standard (Clockwise). It appears the only change in manufacturing these four fans is the blade length.

I apologize in advance for boring some of you with tedious information but for those of you that have experienced how difficult and frustrating it is trying to find out the specifications on fan clutch fans and fan clutches I hope you may find this information helpful.
In closing I would like to add, in my search for fan clutch fans and fan clutches I emailed the various suppliers and stated how critical the specifications are when trying to purchase these items and knowing they will marry together because the information is stated clearly allowing you to make a selection without a dozen phone calls and emails. The lack of information on these products is uncalled for, just my opinion.
So you got parts in a box, that were in a box?
 

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I’ve been quietly following as I may need to replace my fan clutch. Thank you for taking the time to document the parts you bought. Will be sure to reference when I’m ready to explore.
 

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Was in a long, slower speed parade last summer. Car got hot a couple of times. Not over heat hot but unusually hot none the less. Would immediately cool down once on open road. Only do this cruise once a year. Never happened before. Generally car is enjoyed on open road and never prone to heat up. Thinking my thermo fan clutch may not be coupling well any longer.
 

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Be aware of this; When I was putting together my cooling system, I went with the Hayden 2747 clutch and a 7 blade oem-style fan. I needed to put a 1" spacer between the WP & fan for correct location into my existing shroud (half in-half out), This particular combination (extra length along with the weight of the clutch) caused a bent water pump shaft when engine RPM's went to 4000. It could have been a cheap water pump (shaft), slight out-of-balance issue, cheap spacer or some other unknown factor. Regardless, this caused me to switch to an electric fan. I'm not suggesting you go to electric - I am just mentioning my experience that happened to me when I was trying to set up my clutch fan.
Brett 🚀 🚀 🚀
 
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