68 BB A/C Fan Blade

[Jeffrey A.]

In reviewing the judging manual states that a A/C car (which mine is) usually have a seven blade, which has a part number and date code is stamped in one or more of the blades. Does anyone one know what the correct part number is for a 68 BB a/c car? Does anyone have any pictures of a correct fan blade for this car they can post for me.

Thanks

[Jeffrey A.]

Re: 68 BB A/C Fan Blade

Attached is a picture of my fan blade. Any comments are welcome. Thank you

[Jeffrey A.]

Re: 68 BB A/C Fan Blade

Attached is a jpg of the fan blade for those that can not read PDF.
Thanks - Jeff

[Joe L.]

Re: 68 BB A/C Fan Blade

Attached is a jpg of the fan blade for those that can not read PDF.
Thanks - Jeff

Jeff------


I don't think that any 1968 Corvettes, big block or small block, C-60 or not, ever used a 7 blade fan assembly. I think that all 1968 Corvettes used 5 blade fan assembly GM #3888366. Some 1969 Corvettes with C-60 did use a 7 blade fan assembly and I think this is what the JG is referring to. That section probably needs to be re-worded a little bit to be clearer.

The fan blade assembly you have pictured I do not believe is even a Corvette fan blade assembly. At least, I don't recognize it as-such. Generally, Corvette fan blade assemblies were unique to Corvettes. I think the one you have originally resided on another Chevrolet or GM car.

The fan clutch is definitely not an original unit for ANY Corvette or other Chevrolet of the day.

[Jeffrey A.]

Re: 68 BB A/C Fan Blade

Joe

Thanks for the info. I know the fan clutch was not right. The fan blade I was not sure. The search for one begins. Helpfully someone will post a picture of a correct fan blade for a BB with a/c

Thanks

[Anthony S.]

Re: 68 BB A/C Fan Blade

Jeff,

The JG is kind of vague on this.

It states that C-60 cars "usually" have a 7-blade fan and non A/C cars have the 5-blade. Some C-60 cars have been seen w/ the 5-blade fan, but with a greater pitch to the blades. It doesn't distinguish between the 327 or 427.

It does not mention any part numbers, only that the part # & date will be stamped on one or more of the blades.

The 53-82 parts manual calls for a 3931002 7-blade fan for 327's with A/C but it doesn't have a part number for the 427's w/ A/C.

Based on this, I found a 7-blade 3931002 fan dated K-67 for my January car (327) to replace the aftermarket fan that was on my car when I got it.

I could be wrong, but I was going on the best info I had at the time.

Anthony

[Grant W.]

Re: 68 BB A/C Fan Blade

Joe

Thanks for the info. I know the fan clutch was not right. The fan blade I was not sure. The search for one begins. Helpfully someone will post a picture of a correct fan blade for a BB with a/c

Thanks

Hi Jeffrey
As far as I know 68 B/B with or without A/C uses the fan blade 3888366 as Joe describes. It has the stamped number 66 or 99, H and Front on it. Here is a pic of them.

7 blade fans 3955182 started to show up on 69 small block A/C cars. I don't think they were factory assembled for 69 B/B A/C cars as they also used the 3888366 fan blades.

Due to cooling issues in the old days I assume people looking for the 7 blade fans 3955182 and started installing them to help cool the cars. I had a 69 435hp car and installed the 3955182. However incorrect for judging.

Then in 70 you see the B/B 7 blade fan with the sharp wing tips made for 70 to 73 B/B A/C cars. The 70 to 73 small block A/C cars continue to use the 3955182 fan blades with the square tip ends.

Now after many years of searching for the correct 68 or 69 435hp fan. It is different from the 3888366 fan blade as I have found out. Not even sure if this fan is used on the 68 L88 as the 68 L88 may have just used the 3888366 fan blade. Any one out there with an original unmolested original 68 L88. Thanks, Grant

FYI there is a 3888366 fan blade on ebay. I think he wants 650.00 for it. However this fan blade is also correct for 65 to 67 B/B cars 400hp 435hp 425hp 450 hp

[Jeffrey A.]

Re: 68 BB A/C Fan Blade

Grant

Thank so the info and taking the time to explain this to me it is very helpful. Jeff

[Joe L.]

Re: 68 BB A/C Fan Blade

Hi Jeffrey
As far as I know 68 B/B with or without A/C uses the fan blade 3888366 as Joe describes. It has the stamped number 66 or 99, H and Front on it. Here is a pic of them.

7 blade fans 3955182 started to show up on 69 small block A/C cars. I don't think they were factory assembled for 69 B/B A/C cars as they also used the 3888366 fan blades.

Due to cooling issues in the old days I assume people looking for the 7 blade fans 3955182 and started installing them to help cool the cars. I had a 69 435hp car and installed the 3955182. However incorrect for judging.

Then in 70 you see the B/B 7 blade fan with the sharp wing tips made for 70 to 73 B/B A/C cars. The 70 to 73 small block A/C cars continue to use the 3955182 fan blades with the square tip ends.

Now after many years of searching for the correct 68 or 69 435hp fan. It is different from the 3888366 fan blade as I have found out. Not even sure if this fan is used on the 68 L88 as the 68 L88 may have just used the 3888366 fan blade. Any one out there with an original unmolested original 68 L88. Thanks, Grant

FYI there is a 3888366 fan blade on ebay. I think he wants 650.00 for it. However this fan blade is also correct for 65 to 67 B/B cars 400hp 435hp 425hp 450 hp

Grant-----


I'm virtually certain the 1968 L-71 fan blade was the 3888366. I believe it was also used for 1969 L-71, too, although it's possible some may have received the 7 blade 3955182. I'm very confident that NO 1968's ever received the 3955182, though. What 1969 L-71 fan blade are you talking about that's "different from the 3888366"?

Also, the 3888366 was not used for the 1965 model year. It was first used for big block applications for the 1966 model year.

[Joe L.]

Re: 68 BB A/C Fan Blade

Jeff,

The JG is kind of vague on this.

It states that C-60 cars "usually" have a 7-blade fan and non A/C cars have the 5-blade. Some C-60 cars have been seen w/ the 5-blade fan, but with a greater pitch to the blades. It doesn't distinguish between the 327 or 427.

It does not mention any part numbers, only that the part # & date will be stamped on one or more of the blades.

The 53-82 parts manual calls for a 3931002 7-blade fan for 327's with A/C but it doesn't have a part number for the 427's w/ A/C.

Based on this, I found a 7-blade 3931002 fan dated K-67 for my January car (327) to replace the aftermarket fan that was on my car when I got it.

I could be wrong, but I was going on the best info I had at the time.

Anthony

Anthony-----


Actually, I doubt very much that the GM #3931002 fan blade assembly was ever originally used for any 1968 Corvette with or without C-60. I would not rule it out completely, but I very much doubt it. It definitely was not used for any earlier Corvette. Rather, with respect to C2 Corvettes, it was a SERVICE-only piece which, in 1972, replaced the GM #3789562 used for some C2's with C-60.

IF any 1968 Corvettes with small block and C-60 used a fan blade other than the 3888366, I think it was likely the 3789562.

[Jeffrey A.]

Re: 68 BB A/C Fan Blade

Grant or Joe

Do you know were I can find an example of the correct Fan Clutch I need for this car. Thanks - Jeff

[Mark F.]

Re: 68 BB A/C Fan Blade

Here are some photos of the fan clutch off my 68 L71. Note that it is dated on the flange 4 8 68 SC.

Mark

[Jeffrey A.]

Re: 68 BB A/C Fan Blade

Mark do you know if they used the same fan clutch for the L36 engine?

[Mark F.]

Re: 68 BB A/C Fan Blade

The Judging Manual is silent regarding specific BB engines so I would assume this fan clutch would be for all the engines for 68. Joe would be more of an authority on this than I. The key to look for are straight fins. If they are curved then it's a replacement and not original.

Mark

[Joe L.]

Re: 68 BB A/C Fan Blade

Here are some photos of the fan clutch off my 68 L71. Note that it is dated on the flange 4 8 68 SC.

Mark

Mark-----


Yes, this is the fan clutch I would generally expect to find on a 1968 Corvette big block. The clutch pictured is a GM #3937771. However, I believe that other fan clutches were used also. As a general rule, I think that earlier 1968 big blocks used fan clutch GM #3916141. This is an Eaton-manufactured unit and has CURVED fins. It's still available today from GM, although its configuration is somewhat different than the originals of the same part number.

I think that later 1968 Corvette big blocks used the 3937771 pictured. Just when the change occurred, I do not know, but I expect it was fairly early in the model year. In fact, there may not have been a discrete time of change; there may very well have been overlapping use.