Hot Rods 1955 Pontiac v8 (287) transmission options

Hey guys,

As the title states, i would appreciate to know what my transmission options are for a 1955 Pontiac v8 287. Automatic. Aside from an adapter plate which also means exhaust manifolds, starter, flywheel, are there any other options? My gut says know but this is home to many experts I should at least ask.


Thanks

Drew


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I put a Muncie 4 speed behind mine. The stuff you need fits up until 1960 and I might sell the stuff I have if you are interested. I also have a 1960 builder 389 if you want to upgrade. Gary

 

Thanks Gary - still working some things out. I would be going automatic, I suppose that makes it more difficult ?


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Hoping not to let this topic die - though it may turn into "who wants a 227" cause it would be hard to spend thousands to retrofit a transmission onto a 150 horsepower v8 who's parts availability is awful and pricey


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I owned a couple of these back in the 60's, out ran the tri-5's with 283's...
Like you, I'd be hard pressed to spend a lot of money on adapters. The money is better spent on a pre-60 389, or depending on your skill set, any of the newer Pontiac engines. Waaaay back we installed a 400 in a Safari, lots-o-work but nice when finished.

.

 

Putting in a newer one wouldn't be a difficult task for me at all, just would be cool to keep that original motor if I could find another transmission for it.

Super cool to hear that you put them through their paces back in the day!


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Any dual range up right hydro with a Pontiac 55-56 flywheel an bell housing should work.

 

Two transmissions bolt right up, single coupling hydro and dual coupling hydro. Of course you need something from 1960 back. Wilcap makes adapters to bolt newer transmissions up.

 

I have found some adapter plates for in the $600-700 range but have found good 350/400
Motors for
Similar that I can hear run and check over, and BOP th400's that are "in great condition" that id probly just rebuild and enjoy and much nice driving car...

If it was as simple as Chevy where I can just throw any trans on it, an overdrive would be lovely

Thanks for the info


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A Hydramatic has a super low first gear so you can comfortably run a 3.08 rear. No overdrive needed.

 

Have you gotten your transmission selection done yet? If not I can relate some experience with my 1955 pontiac single coupling hydramatic I put in my original 49 with a 1958 Pontiac engine and it was absolutely beautiful so let me know and I'll give you the full story.

 

73RR, back in the day 55 Pontiacs with 287 engines were known as notorious slugs that couldn't get out of their own way. I've never heard any of them referred to as being a hot rod. A good friend of mine owned a 2 door standard shift model that was pitifully slow. So I'm very familiar with their performance and not just woofing.
Regarding the claim they out ran Tri 5's with 283's sounds more then a little fishy. Trust me I've had a few high revving 283 Tri 5's that a 55 Pontiac 287 wouldn't run away from. So have countless others.

Gary

 

There was a guy Named Jim Hand who out ran a few 283,s with those early Pontiac engines. Ive got a 55 truck with a 287 and stick trans. Never raced it against a 283. But its seems to have a bit of power. There are lots of factors that can make any mill into a dog. loose timing chain, poor tune up worn internal parts the list is manifold. Now heres some trivia. The 287 Pontiac and 292 ford use the exact same piston rings.

 

I don't think Mr. Drewl is attempting to build a butt-kickin' hot rod, if I interpret his questions so far. So bad mouthing his 287 as a "boat anchor" isn't necessary. For what it's worth, my '58 - 370 CI Pontiac in my original '49 Ford with the single coupling '55 hydramatic (bolts right up, no adapters, no problems) kicked butt all over south Texas back in the early 60's. Let's see how he responds to the above first....

 

Quick question for ya, you would know and I would guess. Can you bolt s slim jim up to that motor? is that what you are calling single coupling?

 

I have no idea what a slim jim is.

 

here is a paste from some other guy on here about the differences:
_________________________________________________
Ok here goes as far as the single/dual coupling differences:

The single coupling hydramatic (in both single and dual range models) uses the coupling as a fluid clutch between the engine and transmission. The transmission in simple terms uses two planetaries with two bands and two clutches to provide 4 forward speeds. A separate clutch and planetary provide reverse.

The dual coupling uses a similar approach to the fluid clutch, the difference being it has its own front cover and uses a flexplate in place of the flywheel on the single coupling hydramatic.

The transmission is very different, with only the two planetaries for the 4 forward speeds being similar. Reverse is similar too. But the differences are in the way the planetaries are controlled. The front planetary is controlled by either a sprag clutch (for reduction) or the second (smaller coupling for direct drive through planetary. The rear planetary has it's own sprag clutch for reduction, and has a rear clutch (which is the same as the single coupling type) for direct drive through the rear planetary.

There is one band and one other clutch that provide control of Lo range holding in 2nd and DR3 holding in 3rd repsectively.

If you available pictures of both models you will see the big differences. The quadrant has a Park position at the extreme left with the remaining positions being the same as the single coupling type. Reverse is only reverse, no parking lock in that position.

More info: single range hydramatics N DR LO R 1938-1951
dual range hydramatics 1952-1956 (cars) trucks 54-64 or
thereabouts, Rolls Royce up to about 67.

Dual coupling hydramatics (Jetaway, Stratoflight, Superhydramatic

Looks like you have done your homework.

If you need more information please PM me as I have manuals of these transmissions.

 

From what I can tell, Slim Jim trans is 61-up, and Pontiac engines changed bellhousing pattern in 61. Unless it fits the same bellhousing as the 56-60 controlled coupling Hydro, it probably does not fit these early motors.

 

It is a name used for a GM Roto-Hydramatic used I believe starting in 1961.They were a pretty compact unit have the torque converter inside the trans case. I'm curious as to why you wish to change the transmission in the first place.Is the old one not functioning? Is it leaking? I find that the Dual Range Hydramatics are very good transmissions if properly adjusted. The 1-2 and 2-3 shifts are usually pretty hard but solid and if they aren't shifting hard they aren't adjusted properly. They will absorb mega horsepower if called on to do so with a minimum of modification. There is a difference between the 55 and early 56 D/R Hydros and that is the output shaft is larger on the 56. I think the 55-56 Olds Hydros will work as well although I believe the Olds uses a different front clutch setup. The downside to them is when they break they are very expensive to overhaul and finding someone who knows anything about them is difficult at best.

As an aside Mercedes-Benz used these transmission innards with their own aluminum case in the 300 series cars in the mid 1950's. I worked as a parts manager at a M-B dealership and the parts catalogs for the transmissions had GM part numbers in them.

 

Keep in mind, the 55 Pontiac used the SLANT PAN HYDRO (55-56 Pontiacs, although some 56 Pontiacs got the dual coupling Hydro, and 54-56 Oldsmobiles), and the bellhousing is unique for that style. The Slant Pan was used to get more leg room through a flatter floor/trans tunnel. Will a Flat Pan Hydro fit the floor/tunnel contour? A Flat Pan would physically bolt to a Slant Pan Hydro bellhousing, and vise versa, but the transmission would be at the "wrong" angle for the pickup tube and pan. Buy a donor car with a 455/TH400; any full sized Buick, Pontiac, Oldsmobile, or even a Chevrolet 454/TH400 from a car/truck/motorhome to donate their powertrain. There has got to be lots of rusted out late 60's to early 80's cars with good powertrains there in New Yawk. The 287 will be harder to find parts for (hydraulic lifters that fit/work is an issue I've heard). Plus, it's a small engine; might as well step up to a bigger one. In high school, a friend of mine had a band; they transported the equipment in his 55 Pontiac Hearse; silver with a black vinyl roof. All stock except for the Astro slotted chrome steel wheels with redline tires and the stick-on woodgrain he applied to the dash (a wrinkled up mess!).
I am Butch/56sedandelivery.

 

Butch and @safariknut thanks for the answer. I couldn't remember when they changed to the slim jim and I have heard even on here that anything after '56 or 7 was a slim jim, no one challenged the information.

I am a firm believer in the slant pan. I have owned several and have a B&M unit now. I wish I could find a book on them or a book that I could copy the information from. There is a lot of conjecture out there about them and I need good solid information before I break mine open.

 

There are GM service manuals for the Dual Range HydraMatic available although most of them say that you need a raft of special tools to rebuild them. I had a friend back east who said that as long as you had a good pair of internal and external snap ring pliers you were good to go.
One problem about replacing the driveline and using a Turbo 400 trans is that most TH400's have a long tail shaft which would require butchering the X member in order to fit it into the car. Finding a short tail shaft TH400 would be a chore;they exist but I've never seen one.

 

So do we know if he has the slant pan transmission? That was what I put in my first '49 and guess what. When I was in high school, in 1961/62, my machine shop guy said we needed a project. So I yanked my Hydramatic, took it apart, and followed all the articles in Hot Rod magazine about what B&M did to hop up that transmission. Turned the drums to get more clutches inside, and a couple other things I don't remember. And no, there were no special tools or anything required to rebuild them. They are very very simple with regard to the drums, clutches, etc. When I put it back in the shoebox, the first time out I busted both motor mounts. So if a 17 year old can do it, I'm sure you can too...
This may be of some use:
http://www.autotran.us/hmparts1.html

http://www.charlietranny.com/Hydramatic Parts For Sale.htm

http://www.fatsco.net/hydramatic.html

on this one, go to the first post on page 4
http://www.jalopyjournal.com/forum/threads/hydramatic-trannys.41737/

good luck.. I have more if interested...

 

56sedandelivery has it right. Replacing the transmission on a 55-56 Pontiac isn't going to do a thing as long as there is a 287 in front of it. The only thing to wake up one of those old Ponchos is a complete replacement of the original under powered drive train. Over fifty years after GM mistakenly introduced the 287 they haven't gotten any faster. They are by far the worst V8 engine GM ever used.
I'm a big fan of Pontiac engines and I've had several 389 and 400 powered vehicles but theres just nothing good you can say about a 287. It is what it is. This is also the first post I ever read where someone extolled the virtues of a 287 and told us how they out ran Tri 5's with 283's. The thought of one of these 287 powered slugs out running a 283 Tri 5 is a figment of someones imagination. BTW, a pre 60 Pontiac 389 would only be a 1959.

Gary

 

i have a complete slant pan hydra-metic for a Pontiac with the bell housing and flywheel i would like to move, pm me if you have an interest i would let it go cheap

 

Short BOP 400's were all over the place.
GTO's
First and second gen . Firebirds
Lemans and Grand Am's
Grand Prix
If using an adapter , why not a Chevy adapter?
Short 400 Chevy,
Pick ups, motorhomes
BB Chevelles and Malibus

 

Call junior

 

I agree that short tail shaft TH400 are common. I wanted a long shaft model and had to look awhile to find one. I think the TH400 has, like TH350, three lengths of output shaft depending on what model line they came in.

Ray

 

Thanks for the info;I wasn't aware they were that common.I had a 65 389 2barrel with a TH 400 behind it that just left with my 57 Safari.

 

Find a set of '57 or '58 exhaust manifolds. Only year with a 2 1/4 outlet and will clear the steering gear in a 55-57 Poncho..