Configuration of fan blade tip 71-72 vs. 73, 454 with AC

[Joe L.]

Re: Configuration of fan blade tip 71-72 vs. 73, 454 with AC

Did 1974 LS4 C60 not use the 095?

Mark------


No, 1974 with LS-4 and C-60 used fan blade GM #346715 which was also used for 1974 small blocks with C-60. The 346715 is a 7 blade fan with "notched" tips. It is a great cooling fan. Combined with a GM #343721 fan clutch it's one of, if not the, best ever installed on a Corvette.

[Mark E.]

Re: Configuration of fan blade tip 71-72 vs. 73, 454 with AC

Thanks Joe. I found the photo below of 346715. It's curious the fan was changed from the virtually identical '73 LS-4. Maybe an effort to reduce the variety of fans used?

fan temp.jpg

[Tom L.]

Re: Configuration of fan blade tip 71-72 vs. 73, 454 with AC

If it matters, I had the '74 fan on my car when I bought it. Was looking for a correct tipped fan for years. When I got one it was obvious how much quieter the tipped fan was. I guess, as Joe noted, that the '74 cooled better. On the other end, I guess the tips do something for noise. Not sure what. Just my experience.

[Joe L.]

Re: Configuration of fan blade tip 71-72 vs. 73, 454 with AC

Thanks Joe. I found the photo below of 346715. It's curious the fan was changed from the virtually identical '73 LS-4. Maybe an effort to reduce the variety of fans used?

[ATTACH=CONFIG]109632[/ATTACH]

mark-----


There was more than just a fan blade change for 1974. The fan clutch also changed. As I mentioned, the combination of the GM #342715 fan blade assembly and the GM #343721 fan clutch produced the best cooling combination ever on a Corvette. Believe me, this combination COOLS. From my own experience, no overheating in Death Valley in July. It is somewhat noisy but it COOLS.

The GM #3991426 fan clutch used for many 1971-73 applications was, to say the least, somewhat deficient even when new.

[Joe L.]

Re: Configuration of fan blade tip 71-72 vs. 73, 454 with AC

If it matters, I had the '74 fan on my car when I bought it. Was looking for a correct tipped fan for years. When I got one it was obvious how much quieter the tipped fan was. I guess, as Joe noted, that the '74 cooled better. On the other end, I guess the tips do something for noise. Not sure what. Just my experience.

Tom-----


The blade tip configuration of the GM #3992095 was for the purpose of noise suppression. So, why was this configuration not incorporated into the 1974+ fan blade? That I do not know. Certainly, there could not have been much, if any, cost savings by deleting the feature.