5 blade fan

[Jeff M.]

Was a 5 blade clutch fan (ONLY TALKING ABOUT FAN BLADE) the same for a small block as it was for a big block. I need to rep[lace my blade and have access to an nos unit that is being sold as a 62-67 small block. From the pictures it looks like the same configuration of blade positions.

[Joe L.]

Re: 5 blade fan

jeff----

The 61-67 small block 5 blade fan assembly, GM #3770529, is NOT the same as the 66-69 big block 5 blade fan assembly, GM #3888366. Both are 17-1/2" diameter and of 5 blade configuration, though. The GM #3888366 fan blade was used for all 1969 Corvettes, big blocks and small blocks, except those equipped with A/C.

By the way, there are a lot of folks who have "access" to an "NOS" (depending upon your definition of the term NOS) example of the 61-67 GM #3770529 fan blade assembly. If you've got access to a GM dealer, then you've got access to the 3770529 fan blade assembly. It's still available from GM for a current list price of $63.20. Fewer folks have access to an NOS GM #3888366 fan blade assembly, though, since it was discontinued in April, 1971 and will very soon be celebrating the 30 year anniversary of its elimination from GMSPO inventory.

[Joe L.]

Re: 5 blade fan

jeff----

The 61-67 small block 5 blade fan assembly, GM #3770529, is NOT the same as the 66-69 big block 5 blade fan assembly, GM #3888366. Both are 17-1/2" diameter and of 5 blade configuration, though. The GM #3888366 fan blade was used for all 1969 Corvettes, big blocks and small blocks, except those equipped with A/C.

By the way, there are a lot of folks who have "access" to an "NOS" (depending upon your definition of the term NOS) example of the 61-67 GM #3770529 fan blade assembly. If you've got access to a GM dealer, then you've got access to the 3770529 fan blade assembly. It's still available from GM for a current list price of $63.20. Fewer folks have access to an NOS GM #3888366 fan blade assembly, though, since it was discontinued in April, 1971 and will very soon be celebrating the 30 year anniversary of its elimination from GMSPO inventory.

[Jeff M.]

JOE, what is the difference

and can i use the small block fan blade? Does it use the same bolt pattern?

[Jeff M.]

JOE, what is the difference

and can i use the small block fan blade? Does it use the same bolt pattern?

[Roberto L.]

Re: 5 blade fan

Hello, last year I got one 366 replacement (Paragon I think) for my SB 70, which is virtually identical to my original damaged fan, check both side by side. Only minute differences in markings. Rivet and blade shape is correct.
I checked a lot of places for original fans without much success, only original used fans, at very high prices and some doubts about critical state of alignment.

It is labeled 66-69 BB but it is the same used in 69 SB, as Joe said and 70 SB too, as my manual trans no air car.

Roberto, NCRS #30019, RMC

[Roberto L.]

Re: 5 blade fan

Hello, last year I got one 366 replacement (Paragon I think) for my SB 70, which is virtually identical to my original damaged fan, check both side by side. Only minute differences in markings. Rivet and blade shape is correct.
I checked a lot of places for original fans without much success, only original used fans, at very high prices and some doubts about critical state of alignment.

It is labeled 66-69 BB but it is the same used in 69 SB, as Joe said and 70 SB too, as my manual trans no air car.

Roberto, NCRS #30019, RMC

[Joe L.]

Re: JOE, what is the difference

Jeff-----

I think the difference lies in the pitch of the fan blades, but there may be other differences, as well.

Mounting pattern to fan clutch is the same and the fan could be used in your application.

[Joe L.]

Re: JOE, what is the difference

Jeff-----

I think the difference lies in the pitch of the fan blades, but there may be other differences, as well.

Mounting pattern to fan clutch is the same and the fan could be used in your application.

[Peter L.]

Re: 5 blade fan

Please double check but I believe the small block fan blade, P/N 3770529 is 17-1/8" dia. not 17-1/2" dia. Pete

[Peter L.]

Re: 5 blade fan

Please double check but I believe the small block fan blade, P/N 3770529 is 17-1/8" dia. not 17-1/2" dia. Pete

[Joe L.]

Re: 5 blade fan

Pete-----

Yes, you're correct. The GM #3770529 fan blade is, indeed, 17-1/8" in OD.

[Joe L.]

Re: 5 blade fan

Pete-----

Yes, you're correct. The GM #3770529 fan blade is, indeed, 17-1/8" in OD.

[Rob M.]

Re: JOE, what is the difference

The BB fan has a blade pitch of 34.5 degrees if memory serves me correctly. I think the SM blade pitch is around 25 degrees.

[Rob M.]

Re: JOE, what is the difference

The BB fan has a blade pitch of 34.5 degrees if memory serves me correctly. I think the SM blade pitch is around 25 degrees.