alright can anyone tell what is correct for a 72 gs stage1 (with out A.C.) is it a seven blade fan or the big five blade fan. any pics or part #s would be appreciated. thanks
A 2 door hardtop 72 GS= 3437 A two door 72 convt. GS = 3467 Either could have a 350 or 455 In 71 if a GS has a 455 then p/n 1488156 applies which is a 7 blade fan. ( the parts book does not require AC) In 71 if it were a 3000, 4000 or a 5000 series car with a V8 and AC, then 1376724 applies and it is also a 7 blade fan. This is the same number used for a 70 GSX. For 71- 72 even with a 455 other combos in these series would have a 5 bladed fan p/n 1185095. We have a 70 GSX stage1 w/o AC and it has the original fan which is 7 bladed. So I am not sure how to interpret that myself except if the same convention was carried forward from 71 it would have been equipped with a 7 bladed fan.
Although it is not clear to me I would think the 71 convention would say if you have a GS with the 455 as opposed to the 350 it would be a seven blade.
I have both '71 and '72 Assembly Manuals and this is what I found. For a '71: 455 with A/C or Heavy Duty Cooling or GSX or Stage 1 - 5 blade fan w/clutch PN#1185095. 350 with A/C or Heavy Duty Cooling - 7 blade fan w/clutch PN#1239013. 455 A series less A/C, H.D. Cooling, GSX and Stage 1 - 4 blade fan w/spacer PN#1235032. B-C-E series - 7 blade fan w/spacer PN#1488156. 350 2bbl less A/C and H.D. Cooling - 4 blade fan w/spacer PN#1235032. 350 4bbl less A/C and H.D. Cooling - Page missing. For a '72: 455 with A/C or H.D. Cooling or GSX or Stage 1 - 5 blade fan w/clutch. PN#118095. 350 with A/C or H.D. Cooling - 7 blade fan w/clutch PN#1239013. 455 less A/C, H.D. Cooling, GSX and Stage 1 - 7 blade fan w/clutch PN#1488156. 350 less A/C and H.D. Cooling - 4 blade fan w/spacer PN#1235032. There is a definate difference between a fan that mounts on a clutch and one that mounts on a spacer. The fans that mount on a clutch have a much bigger center hole to allow it to fit over the flange on the clutch. The fans that mount on the spacers have a small hole, just like a pulley. :Comp: None of this completely matches what is in the Parts Catalog, BTW, but I suspect this is due to parts being superceded as they were discontinued. My parts manual is from 1983. I studied both assembly manuals and my parts manual very closely and about drove myself nuts, but I feel pretty confident this accurate.:TU:
ok Darren let me get this straight with AC 5 blade fan?, with out AC a seven blade? or did you right it backwards? now i'm confused
NO, NO ,NO.... This combo clearly gets fan #1185095. I have two Assembly Manuals that clearly show this. I double checked this myself and the Assembly Manuals don't lie. This is also confirmed in the Chassis Manual, at least for '71. All 455 with A/C or heavy Duty cooling got the 5 blade. There's even a picture of a 455 w/AC in the Chassis Manual that clearly shows a 5 blade fan with a clutch. The 5 blade fan is a 20" fan, the 7 blade is only a 18" fan. Your Stage 1 should have a 5 blade fan. I have a set of dealership Parts Manuals, and nowhere does it say that a 455 gets a 7 blade fan. It only says "30-40-5000 V-8". The part # is 1239013. This is the fan that the Assembly Manuals show for the 350. My manual also shows this PN for the '70 GSX as well. You are assuming that because your '70 used the 18" 7 blade that all years did, but this is not the case. Be glad to scan some pages if anyone is interested:TU:
I think the difference may be you are looking at the catch all line that says 71-2 455 gets 1185095, a 5 bladed fan except the following: (While I am looking at the line above that which says) a 3437 with a 455 (which is a GS with a 455) gets a 1488156, a 7 bladed fan. And the line above that which says all 3 4 and 5000 series cars with AC and a V8 gets 1376724, a 7 bladed fan. ( the 3,4 and 5000 series includes all specials , skylarks and GS cars) At least that is how I interpreted it.
Well, I believe I can explain this...... It is possible that the listing for the "'71-'72 455 eng. 1185095" is the one for A/C and H.D. Cooling and Stage 1 cars and the listing for the '71 3437-67(455 eng) is for the none A/C cars. This would match exactly to what the '72 Assembly Manual says, and I would be willing to bet that the change to the 7 blade on the '71 none A/C cars occurred mid-year, as something in the Chassis Manual points to this as well. I am curious what year your Parts Manual is from, as it is completely different from mine. Yours has all the same numbers that the Assembly Manuals show except for the 350 7 blade number, and mine is the exact opposite. Mine is from 1983. I think 1239013 and 1376724 are the same part. Fascinating stuff. I won't be able to scan for a few days, but will share the info I have when I can......I wish you could see the Assembly Manuals so you could get the whole picture. It would appear that we are both correct.
you can say that again, i just fell out of my chair. i thank you guys for all the info and hope to get this resolved, i was always under the impression that my car should have a seven blade, but one of the more knowledgeable buick guys up here tells me he's pretty sure my car should have the big five blade fan. o No:
My money is on the 7 blade. :TU: I'll look it up this weekend if I get a chance, so many NCAA games, and so little time.:grin:
I have TWO 71 Asm Manuals. One from early in the model year, the other at the end...BOTH say 7 blade fan.:3gears:
