66 327 A/C fan

[Jim H.]

I am looking to replace the OEM 5-blade fan on my '66 C2 327 w/original A/C with an upgraded 6 or 7 blade fan. The NCRS judging manual indicates OEM 7 blade fans are sometimes found in A/C applications on '66 C2s. Part No. 3955182 (7 blade 66-69 427) has been suggested. Is this correct and, if not, what is correct for my application? Is there any interchange w/other 7 blade OEM GM fans for Camaro, Chevlle, Impala, etc.?

[Joe L.]

Re: 66 327 A/C fan

I am looking to replace the OEM 5-blade fan on my '66 C2 327 w/original A/C with an upgraded 6 or 7 blade fan. The NCRS judging manual indicates OEM 7 blade fans are sometimes found in A/C applications on '66 C2s. Part No. 3955182 (7 blade 66-69 427) has been suggested. Is this correct and, if not, what is correct for my application? Is there any interchange w/other 7 blade OEM GM fans for Camaro, Chevlle, Impala, etc.?

James------


I don't think that any 1967 Corvettes with or without C-60 ever used a 7 blade fan. Your 5 blade fan is likely a GM #3789562 which was used for 1967 Corvettes with small block and C-60.

The GM #3955182 is a 7 blade fan. However, it was never originally used for any 1967 Corvette. In fact, it did not even exist until 1969. It can be used for a 1967 Corvette, though, but it will be "incorrect". Also, it's a very hard piece to find, not reproduced as far as I know, and will be very expensive if you do happen to find one.

You could probably improve your cooling fan performance if you used the GM #3888366 fan which was used for 1967 427 applications. It's still a 5 blade fan but I believe it has a greater angle on the blades. This fan is also very hard to find and expensive. However, a reproduction is available for about 200 bucks.

[Jack H.]

Re: 66 327 A/C fan

Why not talk about why you want to deviate from factory stock (5-blade) to a 6 or 7-blade fan? The original should work A-OK unless you have other cooling system issues (worn/aged radiator, fan clutch that's not up to speed, engine construction deviations, Etc.).

If the alternative issues are afoot on your car, it might be best to find/fix them then 'bandage' the situation via a fan transplant...

[Edward J.]

Re: 66 327 A/C fan

Why not talk about why you want to deviate from factory stock (5-blade) to a 6 or 7-blade fan? The original should work A-OK unless you have other cooling system issues (worn/aged radiator, fan clutch that's not up to speed, engine construction deviations, Etc.).

If the alternative issues are afoot on your car, it might be best to find/fix them then 'bandage' the situation via a fan transplant...

Jim, Jack does have valid points on your situation, I have seen that even with all the above working correctly and still have a occasional problem with the car idling in traffic on those hot days even with the A/C on or off,and the temp slowly moving up the scale, On the C2 cars they really have a limited air flow situation. so in traffic Your sucking the the air from the car in front of you thats more than likely 120+ degrees and your cars already running 200+ degrees so where can you get some cool air to help with you problem? anyway you see what your cars up against in certain driving situations. Jack will atest that this problem of overheating has been up on this site many times before and is a common topic. So check the operation of the common problems first if all is good what elses can you do?

[Peter L.]

Re: 66 327 A/C fan

James - In spite of the ambiguity of the statement in the 1966 Corvette TIM&JG there is a documented case of an early 66 production sb C60 equipped Corvette with some 1965 C60 production parts including the 7-blade fan blade assembly. Pete

[Loren L.]

Re: 66 327 A/C fan

James------


I don't think that any 1967 Corvettes with or without C-60 ever used a 7 blade fan. Your 5 blade fan is likely a GM #3789562 which was used for 1967 Corvettes with small block and C-60.

The GM #3955182 is a 7 blade fan. However, it was never originally used for any 1967 Corvette. In fact, it did not even exist until 1969. It can be used for a 1967 Corvette, though, but it will be "incorrect". Also, it's a very hard piece to find, not reproduced as far as I know, and will be very expensive if you do happen to find one.

You could probably improve your cooling fan performance if you used the GM #3888366 fan which was used for 1967 427 applications. It's still a 5 blade fan but I believe it has a greater angle on the blades. This fan is also very hard to find and expensive. However, a reproduction is available for about 200 bucks.

Joe, he says it's a '66 not a '67 - this topic is complicated enough .....

[Joe L.]

Re: 66 327 A/C fan

Joe, he says it's a '66 not a '67 - this topic is complicated enough .....

Loren------


Yes, you're right. I blew it. I cannot figure out how I thought he was talking about 1967.

Some earlier 1966 Corvettes with C-60 did originally use a 7 blade fan of GM #3853943. I don't know where one would find one of these, though. It was a Corvette-only piece. It was discontinued from SERVICE in August, 1977 and replaced by a fan that had been around since 1968 and used for other Chevrolet applications, GM #3931002. The latter was discontinued without supercession in September, 1986. The 3931002 is a lot easier to find than the 3853943, though.

[Jim H.]

Re: 66 327 A/C fan

I appreciate all of your advice. My entire cooling system is new per OEM spec (new OEM Harrison alum rad, OEM shroud, fan, belts, water pump, etc.) and well sorted. My issue is exactly as you guys describe - fine at speed but a little hot at idle (not too hot - but I hate to see 210 at any time). Purely a function of air flow at rest. Our So Cal summers are challenging for any cooling system (110 degress, sometimes hotter). And my practice is not to use the A/C (I learned that thru a succession of 911s). My purpose is to retain the OEM 5 blade and if there is an OEM enhanced equivalent that will draw more air - I figure that's cheap insurance for my motor. You've given me something to chew on. My next stop are the threads on cooling systems to make sure I've got everything dialed in correctly.

[Bryan M.]

Re: 66 327 A/C fan

I appreciate all of your advice. My entire cooling system is new per OEM spec (new OEM Harrison alum rad, OEM shroud, fan, belts, water pump, etc.) and well sorted. My issue is exactly as you guys describe - fine at speed but a little hot at idle (not too hot - but I hate to see 210 at any time). Purely a function of air flow at rest. Our So Cal summers are challenging for any cooling system (110 degress, sometimes hotter). And my practice is not to use the A/C (I learned that thru a succession of 911s). My purpose is to retain the OEM 5 blade and if there is an OEM enhanced equivalent that will draw more air - I figure that's cheap insurance for my motor. You've given me something to chew on. My next stop are the threads on cooling systems to make sure I've got everything dialed in correctly.

James,
This could be what you are looking for. Bryan
http://www.parts123.com/parts123/yb.dll?parta~dyndetail~Z5Z5Z50000370a~Z5Z5Z5AADNE~ P250.00~~~~S32G0DKQ0468101278250G~Z5Z5Z5~Z5Z5Z5000 0370a

[Jim H.]

Re: 66 327 A/C fan

Bingo! Thanks very much, Bryan. That is exactly it.

[David S.]

Re: 66 327 A/C fan

You may also want to consider switching to a Milodon high flow 160 or 180 degree thermostat.

-Dave