[Steve Barcak]

I am starting this thread with the intent for all of us to share valid information on interchange of engine and trans parts for these years. It would be Okay to expand it through '64/'65 too if wanted.
I'll be posting '55 287 w auto trans pics and '60 389 w auto trans pics soon.

The crankshaft register ( center hole ) and bolt pattern is the same on a '55 and on a '60. I was able to fit the '55 flywheel to a '60 engine and vise versa. I just actually did this myself so it is not heresay, out of a book or manual or third party.

Pics coming.

Anyone who wishes to contribute here, great, just I want it to be first hand so we know it is for sure not 'probably fits'. This thread can be used for long term knowledge of interchange.
I will also be adding this info/pics to my web site.

Steve Barcak www.pontiacheaven.org

"Real Pontiacs only.....no corporate nonsense!"

[axle]

This is great news and needs to be done as more & more people are using early stuff again.

[PITTSBURGH 64]

Great idea Steve.
I sometimes wish this was the 55 to 64 or 66 B body section.

[Steve Barcak]

Yes, Performance Years screwed up big time by separating the 61s and 62s as they share so much. It should have been 55-60 or 55-64. That is about my only complaint about this fine board. They will not change it either, it has been brought up before. The 61-62 ( and 61-64) guys have to cover both areas.

To Start, here is the back end of a '55 287 (left) and a '60 389 (right). Most of us know this but, not everyone. These pics prove that 55-60 Pontiac V-8s have the same bellhousing pattern


Steve Barcak www.pontiacheaven.org
"Real Pontiacs only....no corporate nonsense!"

[Steve Barcak]

Here are pics of a '55 Dual Range and a '60 Dual coupling ( Hydro ).
Dual range has an angled lower pan and also another pan/cover on the left side.
I just pulled both of these so they are definately out of a '55 and a '60.

First pics are the '55 trans....
To remove it, you must unbolt a million converter bolts, they are 3/8" fine thread. Trans fluid wil leak out so have a pan ready, then upbolt the 7/16" coarse bolts to separate the adaptor and the trans itself. Pull the trans back and then it is lowered out of the bell adaptor. It does not slide straight back like a 350/400 thm.

Steve Barcak www.pontiacheaven.org
"Real Pontiacs only....no corporate nonsense!"

[Steve Barcak]

Next are pics of a '60 Hydro. It is removed in a very similar way as the '55 unit except there are only a half dozen converter nuts, 5/16" fine thread.

Steve Barcak www.pontiacheaven.org

"Real Pontiacs only....no corporate nonsense!"

[Steve Barcak]

Now, here are pics of them next to each other with their adaptors and flexplates/flywheels. The '55 unit is on the blue barrel and the '60 is on the ground.
The '55 uses a heavy, cast flywheel. My understanding from the trans thread is this was used in '55 and part of '56, correct?

The '60 uses a modern looking, stamped flexplate and is about the same weight as a 300/350/375/400 plate though it is different. Not totally sure just yet of its interchange but it would seem to at least fit '55-'60 crankshafts.

Steve Barcak www.pontiacheaven.org

"Real Pontiacs only...no corporate nonsense!"

[Steve Barcak]

Here are the flywheel/flexplates to compare. '55 on left and '60 hydro on right on each pic.

Engine side is left pic, trans side on right pic.

Steve Barcak www.pontiacheaven.org

"Real Pontiacs only....no corporate nonsense!"

[stevep]

Originally Posted by
The '55 uses a heavy, cast flywheel. My understanding from the trans thread is this was used in '55 and part of '56, correct?

Steve Barcak [url

www.pontiacheaven.org[/url]

"Real Pontiacs only...no corporate nonsense!"

The 55 Dual Range was in some 56's. I don't know if there is any rhyme or reason to it. I do not think that you could get a Dual Range in a 56 Star Chief. I think it was only available in the 56 Chieftains.
BTW, Pontiac only used the "Slant Pan" in 55-56. Olds used their version of the "Slant Pan" from 54-56. With 56 having both Dual Range and Dual Coupling, like Pontiac. The Olds unit had a different bell housing and a longer tail.
The 55 "heavy cast flywheel" is really the front torus (converter) cover, so it's actually part of the trans.

[stevep]

The Dual Coupling flex plate fits (1) 56-57 and (2) 58-60 and (3) 61-64.

[59safaricat]

Speaking of flexplates, does anyone have a spare they’re willing to sell that will fit a 59 389? I bent mine in the process of removing it from the crankshaft.

[Jack Gifford]

Great idea for a thread, Steve.
Before I try to add anything, I want to get some of the foregoing terminology squared away.

> '55-60 automatic transmissions did not use any [torque] "converter"- they used only 2-element fluid couplings. A fluid coupling can be furnace-brazed and cut for higher stall, in much the same manner as a torque converter- but it does not have the torque multiplication of a converter.

> The Dual-Range Hydramatic did truly use a "flywheel" which, as already noted, served also as the front torus cover ("Torus" is any doughnut-shaped item). But the flywheel was high-tensile steel, not cast iron. It has the starter teeth machined into its rim, rather than using a separate ring gear. Trivial point? No, not with respect to safety. There's no safety concern with zinging that old torus to whatever your engine can muster- some early blown drag cars with HydroSticks spun them to 11,000 RPM. NHRA rules took this into account, only requiring shields around the hydro gear case itself (due to the high speeds of pinion gears in the planetaries), no shielding of flywheel/coupling area required (the 30-bolt torus cover was also high-tensile steel).

Steve- do me a favor, and see if I remember correctly- that to bolt the '55 Hydro flywheel to the back of a 389 crank, you need to put a small chamfer on the outside diameter of the crank flange to clear where the flywheel's torroidal shape extends forward of the flange's surface. You have to look closely, to see whether the flywheel is actually fully seated against the crank flange. It's possible that I used later than a '60 crank when I had to do this- it was a long time ago. Thanks.

I recently glanced at an old Hot Rod article from, maybe '63, titled "The lowdown on engine weights". The listed weights were with all accessories (starter, carb, belts, etc.) but no flywheel of flexplate or bellhousing. I was surprised to see the '55-58 at 30 lb. heavier than '59-60 (685 vs. 655). I never really "studied" the two blocks side-by-side, but am curious about the difference. I'm sure the early cranks are no heavier than a 389 casting, so were the blocks possibly more beefy somewhere? The "easy" answer would be cylinder wall thickness, but I'm not ready to believe 30 lb. worth. Yeah, I've bored an early block way over (3/16" over)- but now with the aid of sonic wall measurement, I find that I was flirting with disaster. Just another thing you could try to look at, Steve.

Notice how these early blocks had the oil filter mounting pad tucked in much closer to the crank centerline than late engines. This made them attractive in narrow-chassis machines, like Steve's dragster.

The Dual-Range did have a 1/8 NPT drain plug in the torus cover- but I've never encountered one that I could get loose!

The slip yoke at the front of the driveshaft is unique to '55 (and '56 with Dual-Range) Pontiacs- not the same as other-year Pontiacs, nor Hydramatics from any other GM division.

[Steve Barcak]

Jack,

OK, I will check a '55 flywheel on my '60 engine.

59safari- I have about 450 Pontiacs right now 1955-1981, I should have an extra '59 flywheel. email me direct steve@pontiacheaven.org


I will be tearing down the 287 to study it for a couple of possible uses.

Thanks guys for adding to this thread
Steve Barcak www.pontiacheaven.org

"Real Pontiacs only......no corporate nonsense!"

[PITTSBURGH 64]

Here are some picts I have.

Here is a photo of my governor swap in my 64 hydro.
The governor with the smaller tip is for higher top speed shift points. Its from a 60 Tri-Power 389 Hydro.

[stevep]

Jack, I have never had a problem removing the torus drain plug on any Hydro.......yet!

[Bill Hanlon]

Originally Posted by pontiac jack

The Dual-Range did have a 1/8 NPT drain plug in the torus cover- but I've never encountered one that I could get loose!

I've removed the torus drain plug on my '57 GMC dual range at least twice with no problem. Used a 6 point socket as recommended in the GMC Shop Manual. Did the same with the torus on the transmission that I removed from a '55 Suburban that I'm putting into my truck "any day now".

[axle]

Steve, I really want the full scoop on the early block - late head , and later block - early head swap. I saw your picture in my thread with the later head gasket laid on top of a 55 block. You didn't answer my question yet, were there any holes that the gasket covered? Let us know. Thanks again for your research in this.

[Jack Gifford]

Originally Posted by Steve Barcak

... I will check a '55 flywheel on my '60 engine...

Looking at your photo of the back of the '60 engine, it appears that the crank flange does have that weight-blob on it that causes the interference with the Dual-Range flywheel. I see that Don Francisco solved it by grinding on the flywheel, instead of chamferring the crank flange like I've done. (See the thread in the "Non-Pontiac Motors in Pontiacs" forum about his Pontiac/HydroStick into '55 Thunderbird, in the Feb'63 Hot Rod issue).

[Jack Gifford]

Originally Posted by axle

Steve,... were there any holes that the gasket covered?...

I'm sure Steve will get back to you soon. In the meantime, here's a picture of a '58 deck. As you can see, it's identical to all other Pontiac V8 decks, with the exception of the little oil feed hole for the rocker studs (above cyl.#4/5).
The second picture is a '58 head, in which you can see the three extra coolant holes between cylinders, just above-center of the bores. There were no matching holes in '57 and later blocks, but I don't know if maybe '55 or '56 might have had them in the block decks.

[Steve Barcak]

Pontiac Jack- " Steve- do me a favor, and see if I remember correctly- that to bolt the '55 Hydro flywheel to the back of a 389 crank, you need to put a small chamfer on the outside diameter of the crank flange to clear where the flywheel's torroidal shape extends forward of the flange's surface. You have to look closely, to see whether the flywheel is actually fully seated against the crank flange. It's possible that I used later than a '60 crank when I had to do this- it was a long time ago. Thanks."

Yes, it does appear that a bit of grinding is needed to the crank flange to fit the '55 flywheel to the '60 389. It does not look like there is much interfereance but, there is a bit. I had Keith look at it too and he thinks the same. Still, register and bolt pattern is the same. Minor work needed to fit. It also would be much easier to verify this if the crank was out of the motor but, this engine is together.

Axle- I'll get to it and post it here.

Another note- the '55 287 does not have the reinforcing rib in the bottom of the block. Books I read indicated that all '55-'60 blocks had this rib. Every '58 and '59 block I have seen had this rib. All of the '60s except for one also have the rib. I have a few 336 GMCs and they have the rib.
Tearing down and checking just one 287 is hardly conclusive but it opens the question about other 287s and now 316s and 347s. did these engines have the reinforcing rib?

This 287s crank is also marked "Armasteel" indicating it is a casting. This is another issue too. Can anyone add to this? Other 287s, 316s having forged or cast cranks?

Tom S told wrote sometime before that he had a 347 with a cast crank.

Every 370 I have seen had a forged crank.

Steve Barcak www.pontiacheaven.org

"Real Pontiacs only....no corporate nonsense!"