[PurelyGTO68]

Not sure how I missed this before....
Here is a page from the GTO Restoration Guide book on this topic.



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[RA1John]

With regards to the assembly plant worker making a mistake or assumption or the plant running out of parts and using whatever they had on hand...

Sure, things were different 50+ years ago at the typical assembly plant compared to today but it's not like they were building cars in their garage.
There were build orders, Broadcast Sheets (or Bingo, Tracking Tell-All sheets) taped to the body, engine, etc. with instructions for the Operator.
When the car came into a station, the Operator didn't simply make a judgment call based on what they felt was right, they installed parts per instructions.
There were also inspectors and material control. If they ran out of screws, someone didn't just run out to the hardware store for more.

Today of course, there are still Broadcast Sheets taped to the body and driveline components but there are also...
Sequenced parts, barcoding, pick-lights, Work Station Monitors displaying specific parts for vehicle in-station, vision validation, etc.
Mistakes still happen with putting the wrong part on car but nothing like 50 years ago when you could have a friend upgrade your axle.

All this to say... If survivor or original, un-tampered with Ram Air cars from '68 have a 4-blade steel fan, it's safe to say that is the fan used on all others.
(unless of course an option called for a different fan).

Then again..... Never say never, right?

[RA1John]

Does anyone have a 4-blade, 19" dia., 2-5/16" pitch fan that they could share a pic of? I'm curious as to how/where the pitch is measured.

Thanks!

[PurelyGTO68]

Originally Posted by RA1John

Does anyone have a 4-blade, 19" dia., 2-5/16" pitch fan that they could share a pic of? I'm curious as to how/where the pitch is measured.

Thanks!

I looked at mine a short bit ago. Not sure how the pitch is measured but I think it's generally rise over run. If that is the case then the rise is about 1 9/16" divided by run of about 3 1/2" (width of fan blade). I believe the math works out to be 2.24 so that is just shy of 2 1/4". If my measurements are off by 1/16" then that could account for the variances from 2 1/4" to 2 5/16" I suppose...



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[RA1John]

Parts catalog, Mar. 1969...





Part # 519834 has a lot of usages. All are 19" diameter with only (1) application noting the pitch as 1-5/8". Where did 2-5/16" pitch come from?

[RA1John]

Interesting...

In the Mar. 1971 Parts Catalog, the 519834 4-Blade Fan is no longer listed. Instead, there is a 9798940 4-Blade Fan that is 19" dia. with 2-5/16" pitch.
This Fan is listed as being applicable for Firebird & GTO Ram Air.



So, apparently 9798940 superseded the 519834 Fan which would mean that factory Ram Air cars came with a 19" dia., 1-5/8" pitch Fan.

Thoughts?

[RA1John]

Here is a 2-5/16" pitch 4-Blade Fan...

[Geoff]

It is no wonder GM gave Pontiac the chop! Ridiculous number of fans with huge inventory costs when 4 fans would have covered the whole model range.

[unruhjonny]

interesting;
That 9798940 fan is the same one I have from a 1973 Pontiac 350 - I suspect many of those have been thrown out over the years.

[68pongto]

The original part # of 519834 makes perfect sense. The 68 RA build sheets show 34 as the fan code, the last two numbers of the original part #. They also show 53 as the spacer code, the last two numbers of the 535253 spacer. I figured the 9798940 superseded the 519834 number. RA1John, do you have any more pictures of your original fan?

[68pongto]

So the original MPC with the original part # says the fan is 1 5/8" pitch. The 1971 MPC with the new number says 2 5/16" pitch. I have a 68 fan that has the 1 5/8" pitch off a 68 Tempest with no A/C and the build sheet has the 34 code. That would lead me to believe the original 68 ram air fans were 1 5/8" pitch since RA and STD. Tempest 8 cyl. have the same part number in the 69 MPC.

[69RamAirIIIJudge]

So my question is, I have a R.A. III Judge non a/c, will the spacer off of my 69 Le Mans parts car with 4 blade work with my 5 blade flex? Is the spacer the same? Or would I be wiser to keep the 7 blade clutch fan that was inside he car with my parts?

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[68pongto]

69RamAirIIIJudge, as long as you have the 535253 spacer you should be fine. The spacer is the same one for 4 blade steel and 5 blade flex fans. The 69 RA III with no A/C should use the flex fan. Not sure what the 69 RA IV used.