72 LT1 C60 Fan Blade GM# 3955182

[Tom R.]

Should I have been surprised to find this fan blade on a 72 LT1 car engine suffix CKY.

What's history of the GM# 3955192 fan blade? Seems like it was used in 68 with big blocks and than some usage in 80 with C60 smallblocks.

[Joe L.]

Re: 72 LT1 C60 Fan Blade GM# 3955182

Tom------

If finding non-original configuration components on Corvettes causes you to be surprised, then this blade should have surprised you when you found it on a 1972 LT-1. The 3955182 fan blade assembly was not used in PRODUCTION after the 1970 model year.

The GM #3955182 fan blade assembly was first used for the 1969 model year. For that year, it was used for L-46, L-36, and L-68 engines with C-60. For 1970, it was used for L-46 with C-60.

Most other 68-70 applications used the 5 blade fan of GM #3888366. However, the GM #3888366 fan blade was discontinued from SERVICE in April, 1971 and was replaced, for SERVICE, by the GM #3955182. So, a lot of 68-70 Corvettes originally equipped with the 3888366 later received a 3955182 if they required fan replacement. The GM #3955182 was available in SERVICE until just a few years ago. It is now discontinued (and, highly sought after). The one in your picture was manufactured in March, 1988.

Finding this fan blade on a 1972 LT-1 raises all sorts of other questions. Here's why: beginning with the 1971 model year, all Corvettes changed to the 2-1/8" bolt circle fan clutch hub mounting. Also, the waterpump pilot OD changed from 5/8" (55-70 style) to 3/4". Consequently, the waterpump pullies changed and the fan clutch changed. Since the new fan clutch was designed for use with a 3-1/4" bolt circle fan blade mounting, the fan blade assemblies also changed. So, mounting a 3955182 fan blade assembly to a 1972 Corvette requires a lot of other changes. Some aftermarket fan clutches designed for "one-size-fits-all" might allow the installation of a 3955182 fan blade assembly on a 1972 Corvette without changing other parts. Otherwise, other parts also have to change to use it.

The original fan blade assembly for 1972 Corvettes with LT-1 and without C-60 was GM #3991420. For 1972 LT-1 with C-60 fan blade assembly GM #3991427 was used. The 3991427 is very similar in configuration to the 3955182---both have 7 blades of the same pitch, OD and similar blade configuration. However, the 3955182 uses the 3" bolt circle for mounting to the fan clutch and the 3991427 uses the 3-1/4" bolt circle. Also, the center hole in the 3955182 fan clutch is 2-3/8" OD; the 3991427 is 2-5/8". A 71+ fan clutch hub will not fit through the 2-3/8" hole of the 3955182, not that it would bolt up to the 71+ fan clutch, anyway.

[Tom R.]

Re: 72 LT1 C60 Fan Blade GM# 3955182

I was skeptical when I first saw the car than observed no TI along with two fuel lines along the rail. But than checking sources, saw where in 72 with LT1...no TI. TI came with ZR1 RPO. Also noted the suspension was "upgraded" to what appears to be the FE7 sway bar and 7 leaf rear spring. But than it had the CKY block.

[Terry M.]

Re: 72 LT1 C60 Fan Blade GM# 3955182

Tom, there was NO TI on Corvettes in 1972 model year. ALL LT1s in 1970 and 1971 got TI. The ZR1 was no different than the other LT1s in its model year in this regard.

[Dick W.]

Re: 72 LT1 C60 Fan Blade GM# 3955182

Tom, first major RED flag is the two fuel lines. Holley equipped engines of this vintage used a single fuel line

[Joe L.]

Re: 72 LT1 C60 Fan Blade GM# 3955182

Dick------

Yes, they did. The ONLY exception was 1971 Corvette with LS-6. That's the only Holley-equipped Corvette that was ever built with a fuel return line.

[Joe L.]

Re: 72 LT1 C60 Fan Blade GM# 3955182

Terry-----

I agree also. TI was last used in any Corvette for the 1971 model year. I have seen references that state that the 72 ZR-1 had TI. Those references are incorrect.