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Old 06-21-2020, 05:49 PM
Mark66 Mark66 is offline
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Default '66 389 and pilot bearing

I am trying to confirm that all 1966 389 crank shafts were machined for the pilot bearing that would have been used if the engine were installed in a B body manual transmission car. Is this correct?

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Old 06-22-2020, 09:58 PM
gtoguys gtoguys is offline
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I changed from a Turbo 400 to a Muncie 4 speed in my 66 Bonneville. I used a pilot bearing, not a bushing. Most Pontiacs had bearings. It still has the original 389. I hope that helps.

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Old 06-25-2020, 11:00 AM
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61-63 61-63 is offline
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If they had not been how would the pilot bearing have been installed on the assembly line? Smart a$$ response I know. I can't respond re '66 cranks but I converted a '63 auto car to std. trans and had to grind a step out of the hole in the end of the crank with a Dremel in order to get a pilot bushing in there. I don't know how they did it on the assembly line at the factory but all of the engine were built at the Pontiac assembly plant, right? I can't imagine they had two piles of cranks, one for auto trans and one for m/t, and made sure they took one off of the right pile as they assembled the engines. Rather I'd think they ran an end mill up into the rear of the crank somewhere along the engine assembly line as soon as they were made aware that that engine was going into an s/t car.

If you are asking because you are converting a car to s/t and are concerned about the pilot bearing fitting, just try it, and if it doesn't fit then run your little finger up into the hole to see if there is a step in there. If there is then take a Dremel with a stone on it and grind the step out. This is what I did and it fixed the problem. Just be sure to grind it out all the way around and not all on one side.

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Old 06-25-2020, 12:40 PM
Mark66 Mark66 is offline
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Thanks. I have always assumed - and have seen it mentioned in previous posts - that all 389 cranks (at least in 1966) were machined identically. Any you reasoning holds water.

I am indeed finally getting around to considering swapping out the auto trans in my "66 GP for a 4 speed manual. I have all of the parts and just need to do it - but trying to work out on paper what obstacles I can expect to run into.

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Old 06-26-2020, 03:54 PM
gtoguys gtoguys is offline
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The biggest obstacle is finding a pushrod boot at the firewall. No one makes a replacement. I cobbled in a boot from a gto. It's too long, but it will work. Then, you will need to weld the cross shaft anchor point, on to the frame. To me that was the worst! I can weld, but no room to maneuver. Keep going on the project, it will be fun when done!

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Old 07-02-2020, 08:55 PM
Mark66 Mark66 is offline
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gtoguys – thanks for the reply. I will use your suggestion for the boot as there seems to be no alternative.

With respect to the mounting of the “Bracket, clutch control countershaft frame” to the frame that will indeed be a headache if not done right the first time. 63gpman provided a good template solution to locating the bracket on the frame in post http://forums.maxperformanceinc.com/...=700014&page=2. I have sourced a bracket that will need some modification but should work. Alternatively I am also hydraulic clutch linkage.

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Old 07-13-2020, 02:16 PM
Mark66 Mark66 is offline
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I think I can answer my own question.

Looking at the Pontiac Chassis Parts Catalog (Oct 1, 1966) there is only a single crankshaft assembly(9782646) shown for all "1966 P/8 389, T/8 GTO".

So that means, it would appear, that the clutch pilot bearing required for all big '66 Pontiacs with manual transmission will indeed fit the crank shaft of a car that originally was equipped with an automatic transmission. No machining required.

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