John S Posted October 3, 2017 Share Posted October 3, 2017 I am looking at a 7 blade clutch fan, I see two types one with straight blades and another type with the blade tips curled in. Which one is original or correct? What type is for the small block? John S Quote Link to comment Share on other sites More sharing options...
John S Posted October 3, 2017 Author Share Posted October 3, 2017 Assembly manual showed PN 347772 for big block. Is it the same for small block? Quote Link to comment Share on other sites More sharing options...
RealRed70 Posted October 3, 2017 Share Posted October 3, 2017 Those are very nice fans. Quote Link to comment Share on other sites More sharing options...
MCfan Posted October 3, 2017 Share Posted October 3, 2017 John, In the RPO C60 (air conditioning) section of the '70 Assembly Manual, they also show P/N 3976064 and 3976065 as possible clutch fans for the V8 engines. I can't find anything that suggests which fan goes with with engine, although all three of them are apparently 7-blade clutch fans. PN 347772 definitely has the curved blades. I bought the one below on eBay for my '70 402 when I added Classic Auto Air several years ago. Quote Link to comment Share on other sites More sharing options...
John S Posted October 4, 2017 Author Share Posted October 4, 2017 John, In the RPO C60 (air conditioning) section of the '70 Assembly Manual, they also show P/N 3976064 and 3976065 as possible clutch fans for the V8 engines. I can't find anything that suggests which fan goes with with engine, although all three of them are apparently 7-blade clutch fans. PN 347772 definitely has the curved blades. I bought the one below on eBay for my '70 402 when I added Classic Auto Air several years ago. P1264717.JPGP1264719.JPGP1264725.JPG I do not have air on the car. But with the L48 350 I have the small radiator with three bolt top cover. I did recore to a three row last year but used an aftermarket flex fan. I talk with a number of people at the Summit cruise ins I attend with Monte Charles and I have been told stories of those flex fans coming apart and one person said it took out his radiator. It's hot in Georgia and traffic is horrible so I usually get stuck in it on 95 degree+days. I was thinking why not use a seven blade clutch fan it should draw in more air and should function fine. I believe the 947772 fan is 18" but also read that on high perf. big blocks a 18 3/8" fan was used. I wonder if that is the 3976064 fan without the curved blade tips. The fan you have is readily available and if it works fine for you it should be fine with mine. John S Quote Link to comment Share on other sites More sharing options...
MCfan Posted October 4, 2017 Share Posted October 4, 2017 John, I just checked and my '70 454SS also has the 3947772 clutch fan. I can't find any info on the other two fans. Quote Link to comment Share on other sites More sharing options...
John S Posted October 4, 2017 Author Share Posted October 4, 2017 Thank you 3947772 is what I'll get Quote Link to comment Share on other sites More sharing options...
John S Posted October 13, 2017 Author Share Posted October 13, 2017 Got the same fan as the one Dennis posted. As far as the clutch goes since I do not have air cond. I am leaning towards the non thermal or centrifugal fan clutch. This type is supposed to lock up at lower RPM and "coast" at higher RPM where as the thermal clutch operates on temp. Any thoughts? John S Quote Link to comment Share on other sites More sharing options...
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