a little early pontiac tech/interchange

[Justin B]

this is for the poncho guys all this came from a 1963 pontiac tech special put out by hot rod magazine so this will only cover the 55-63 engines. i tried to scan it but you can't read it very well so i'll try my best to tell you the most common things that come up

ok, first intake manifolds, i've seen a couple post concerning these. first most manifolds that come up for sale are for the 60 and later engines, this said in most cases you can adapt these to the earlier engines. what you have to do is relocate the water outlets in the intake back about half an inch. you use a die grinder and move the outlets back until they line up with the heads (make a template of the outlets) them just weld up the area that the wateroutlet overhangs in front of the early heads,then use a big belt sander to flaten up the mating surface on the intake. moving the water port back will not effect anything else on the intake as the fuel runners are in the same position on the early and late intakes. there's a local guy that is running this way with a edelbrock intake on a 59 389 and has been doing so for a couple years with no problems. i am not sure if you could reverse this procedure and run a early intake on later heads,the book doesn't cover that one, but i don't see why you couldn't.

ok now some itake manifold part #'s and what they fit as often it is hard to tell by looking, and alot of people selling used ones don't know what they fit either, some aftermarket intakes will fit both early and late engines.first 6-2 intakes, weiand # wp6 fits 55-63engines, offenhauser #3946 fits 55-60, #5163 for 61-63, edelbrock #mlp6 fits 55-60, and #mlp61 fits 61-63. now some 3-2 intakes edelbrock # p-303 fits all 55-63, offenhauser #5161 fits 61-63, wish there were more listed but thats it for 3-2s. now 2-4 intakes edelbrock #p-22 fits all 55-63, aoffenhauser #5029 fits 55-60, and last a weiand blower itake # wp-671 for 55-63. i wish there were more part numbers but that was all that was listed in the book. there have deffinitly also been alot more made by others after this book was published. my best advice if you are going to a swap meet looking for one bring along an old gasket and make sure everything lines up.

ok some valve covers, offenhauser #5043 fits 55-63, edelbrock #4130 fits 55-60, edelbrock #4165 for 61-63, and weiand #wp542b fits61-63.

now some itechange stuff first the easy stuff all distributers fit all years, as do camshafts. don't know about the later engines but the first series rocker arms are intechangable with small block chevys, saved me about $40 on roller rockers by buying the chevy part number instead of the pontiac one. exhaust manifolds only intechange with the corresponding series engines ie 55-60 and 61-63 as the early heads had the exhaust crossovers in the so there were actually only 3 exhaust ports on each side when you look at them. heads can be changed on all year pontiacs will some minor modifications as all pontiacs are basicly the same block, no such thing as a big block pontiac. putting 60-63 heads on the early engines is simple the just bolt on, all you have to do is pop out the freze plugs so the water pump can still pump through them. i have done this and it is just about as basic as it can be, just bolt em on. you can also put early heads on the late blocks but i'm not sure what that entails. you can even run the heads on the later 60s stuff like a 455 so you can use a modern trans, once again not sure what this entails but have seen a few done like this, another local with a 421 tri power car is using a 68 400 ci block but his origional heads so he can keep the tri power looking stock, he backed this with a 700r4 so now he's even got overdrive. oh you can even interchange the heads on the tempest four with the v-8 engines.
the front covers from 55-59 interchange book doesn't cover this but i ran a 59 389 in a 55 starchief and used the earlier front cover because thats were the motor mount is on a 55.

now the hard one transmissions, automatics55 and 56 hydromatics are obviously the one everyone seems to want for a street/strip car because of the famous b&m hydro stick conversion. this can only easily be done to these two years because 57 and up have a secondary hydrolic coupling. for those not familiar with this hydrstick conversion it makes it so the driver has to do the upshifting manualy. these are also the trans that came in oldsmobiles and cadillacs of the same years and were put into so many famous gassers in the early sixties. these trans are intechangable with the engines through 60 but you have to do a little bit of grinding to make them seat the flexplate and fluid coupling together. they do not interchange easily with the later engines as the starter is located differently.

well thats pretty much all i got right now unless someone is building a race engine and wants some of mickey thompsons specs as this book also covers that. if any other poncho guys want to add some more to this post feel free as i know i didn't cover everything.

[Rocky]

The trick on slipping the 55-56 hydro [and, I'm told the 56 only has an extra pair of clutches] against the 59-60 389 engine is to grind the sharp edge off a portion of the crank shaft flange so the engine half of the fluid coupling will fit flat against the crank flange. If you don't do this procedure, the resulting gap between parts will leak fluid like a mofo. If you start up the engine, you'll most likely take out the front pump of the tranny with the wobbling coupling.
Get the 55-56 throttle/kickdown linkage with the hydro to control kickdown and tranny line pressure...

[safariknut]

Just a small addition on the trans issue:There is a difference between 55 and early 56 transmissions(the late 56 is actually 57 style).I found this out when I purchased a 56 trans to replace the leaker in my 55.
Went to put it in and everything was the same until I got to the driveshaft:the output shaft spline is different(larger)on the 56.I had luckily gotten the 56 shaft with the trans so no problem I thought.WRONG!The universal joint was different also.Not only was it larger but it attached differently.The 55 rear universal has what look like pillow blocks where it bolts to the flange whereas the 56 uses the more common U-bolt.Can't swap them either because the flange is about a half inch wider with larger diameter cups.
Wound up taking both shafts to a driveshaft shop,having the front yokes cut off and the 56 yoke welded to the 55 shaft.Luckily the driveshaft diameters are the same.Everything else bolted up perfectly.
safariknut

[56olds-ERDY]

great info on the tranny stuff.this helps me out greatly since i had just got a early 56 poncho trans that was bolted to an olds.i plan on using it behind my 394 im building.i wasnt aware of the rear spline differance.ill compare it to a 55 olds one i have here.i have the driveshaft frome the 55 too.nothing from the 56 poncho though.hope there the same or i wont have a bolt in anymore.the motor,and trans did have olds car mounts though.maybe poncho's are different.(some years)
anymore differences you guys know?
eric

[Justin B]

just thought i'd bring this back to the top cause of all the recent pontiac pontiac questions

[Mike Landwehr]

just thought i'd bring this back to the top cause of all the recent pontiac pontiac questions
and thanks for it , now where the hell is park on them Hydro's -58 specifically i found neutral all the way to the bottom (towards me ) and all the way forward for REV. no park?

[safariknut]

and thanks for it , now where the hell is park on them Hydro's -58 specifically i found neutral all the way to the bottom (towards me ) and all the way forward for REV. no park?
Mike:
On a 58 the sequence on the shift quadrant from left to right is: P-N-D2-D1-L-R. Given that,Park should be all the way to the bottom. The early transmissions used R for parking as the parking pawl was held form engaging by oil pressure(engine running).When the engine was shut off,the pressure bled off and engaged the parking pawl which is why when you shut off an early car,you should keep your foot on the brake for several seconds until the pawl engages.If you don't and the car is allowed to roll sometimes the force encountered when it finally does engage will snap the end of the pawl and PRESTO!;no park!

[Mike Landwehr]

Mike:
On a 58 the sequence on the shift quadrant from left to right is: P-N-D2-D1-L-R. Given that,Park should be all the way to the bottom. The early transmissions used R for parking as the parking pawl was held form engaging by oil pressure(engine running).When the engine was shut off,the pressure bled off and engaged the parking pawl which is why when you shut off an early car,you should keep your foot on the brake for several seconds until the pawl engages.If you don't and the car is allowed to roll sometimes the force encountered when it finally does engage will snap the end of the pawl and PRESTO!;no park!
now I get it, that again may explain a couple things , Thanks ,Mike

[geemann51]

Nicely done Justin.....

[Brandy]

Nicely done Justin.....

Well done to all of you!

x
Brandy

[Rocky]

Safariknut is right about the park position. It means when your doing close-order-drill in the front seat with your girlfriend at the drive-in movie, be careful not to knock the shifter up outa reverse with your ass or leg or whatEVER! Don't axe me how I know.

[Mike Landwehr]

Safariknut is right about the park position. It means when your doing close-order-drill in the front seat with your girlfriend at the drive-in movie, be careful not to knock the shifter up outa reverse with your ass or leg or whatEVER! Don't axe me how I know.
GOD!, I miss drive ins ;D

[Chandler]

thanks for the info

[rustynewyorker]

I'm not an expert by far, but I can share what I've picked up over the last 10 years or so -

I nabbed a set of '60s tube headers at a swap meet last spring for $2, because they were Pontiac. A guy had the top end of a '57 347 for sale, so I used his head to check. They'll bolt up physically to the early head, at least. I ran my '60 last with the trapdoor in the manifold wired open when the spring broke, it just ran like crap in the cold until it got warmed up.

You can put a late front cover on a block as early as '59 - did so with a 301, which is also a good source for an HEI distributor since they're crap thinwall castings with lousy heads and good mostly for boat anchors. The oil pans will swap too. Have had all three on a '59 389 block. The only real advantage here is the water pump is easier to find. There are some issues with the reman pumps from Napa for the 4-bolt pump applications that have a small stamped impeller and may run the wrong direction, casuing overheating issues.

Supposedly the 4-cylinder Tempest heads will up the compression a bit when used on a V8. That motor is just a 389 with one bank lopped off anyhow.

A 59-60 389 bolts into a 55-57 using the stock mounts and is cheaper to rebuild than the stock motor - +.055 makes it a stock bore 400 if you want to go that far, which is about the cheapest Pontiac rebuild kit out there. Lower end is all the same and a neoprene rear main seal is available to cure that leak issue. After 60 they changed the front of the block slightly so you can't use the stock '55-'57 mount. You have to use the early cover I believe too.

59-60 side mounts are different than 61-up, except the '69 Gran Prix used them again - they are prone to seperation when the rubber gets old, I broke both in the '60 and when they come loose the motor lifts and jams the accelerator linkage down. On the bright side while you wait for someone to ship you a set, you can wrap them with a coathanger around about 10 times and drive the car if you have to - and just keep an easy foot on it if you have to nurse one home with a bad mount.

You can change the 59-back cannister oil filter to a new style spin on with about any GM V8 filter mount. I think I have a 301 piece on mine, but in the engine shop I compared it to a Chevy piece and they were identical. I know for sure it works on '59, not as sure on the older (I'll get a junk '57 347 to play with this summer and test fit some of this stuff to it). The 60 has the spin on from new, at least mine does.


If you change the cam in a 59-60 block be prepared to change the whole top end. I have a different cam in mine and have been told by several people to change the rockers so I don't bounce valves off the pistons in it. Trouble is no one can tell me exactly what I need to do to it even though I lucked out and came up with the cam spec sheet. I'm thinking I should put a stock cam back in it and use the one in it now in another motor.


Some trans tips -

'55-57 manual trans bells won't work with newer transmissions, but the 58-60 (which is a pain in the butt to find) will. But you can run a 37-57 Buick heavy duty 3-speed with the early bell. It converts to open drive with Olds parts, or use the Olds trans if you can find one. The 55-56 Pontiac manual trans is a throwback to the 54-back cars and is on the weak side, at least I've been led to believe. Might be they didn't get the heavy duty trans.

A guy tells me the Hydro you can store almost indefinitely if the front pump is good and the correct fluid is used. I wouldn't pull one out of a 20-year junkyard resident without going through it, but I should be able to use the one in my '60 that's been parked about 5 years now.

There's a crank difference, too - I need to look up again exactly but some later trans mainshafts are a little deeper than the pilot hole in the crank, which you'd need to machine out to run the later trans.

Adapters are made for 61-64 blocks to late transmissions. For those who don't know already, the biggest issue here is the starter. You might get the late trans to physically bolt onto an early block - bolt patterns are close at least on top - but the older ones use a bellhousing (even the Hydro uses a maybe 3" deep cast piece as late as '59) and the starter bolts go through this, parallell to the crank. Later ones use an ear on the block.


Rearend tech:

The 58-64 posi with 31-spline axles is the stronger piece. It will fit into a '57 housing to bolt into leaf spring cars - you can put the '57 housing into the '55-'56, and also into 55-57 Chevys. The '57 is better than the 55-56 with I believe 28 spline axles, but the 58-64 is nearly bulletproof. Why can't you use the 58-64 housing? Only because they had coil springs. The brakes on these are better too and can swap to the '57 housing.




One more thing for guys building 55-57's - Power steering conversions. A GM 605 box (78-86 Monte Carlo, Malibu and clones) will go in using one stock hole and the stock pittman arm. Rodder's DIgest ran an article a long time ago on this conversion, you drill two new holes and run some tubing through so the frame can't compress and it's good to go. If you change motors in this car, there is not a lot of clearance running stock steering for the exhaust, so this can be a must-do swap.



There's a couple of good guys on the Pontiac-1950s e-mail list at yahoogroups.com, if you have speciific questions.... there also is a good archive of messages on these swaps there.

[BARNETT]

Good timing on this excellent info!

[Rocky]

Good info Rusty but I have to argue one point with ya. The rear axles from 57 and 58 both have only 29 splines, Pontiac didn't go to 31 spllines until '59 [neither did Olds!] and pontiac didn't offer a posi until '58. That makes those '58 Posi's really valuable as it was a one-year option and they are the only year posi that will bolt into a leaf-spring 57 housing, using stock 57-58 axle shafts. Later pontiac axle shafts are too long and they're 31 spline.
If you slide a 59-64 posi 3rd member into your 57-58 narrow housing, expect to go looking for axles. I've tried using the 59-64 Olds 31 spline shafts as they're shorter than the same-year pontiacs [Wide track ride, remember?] and shortening them to work in the narrow 57 Pontiac housing but there's not very damn much splined shaft left after shortening.......I dunno about this shit..I may hafta bite the bullet and buy aftermarket axleshafts.
I'm told you need to grind on the early housing to fit the later posi 3rd member into it too.............I have one but haven't tried to bolt the '64 posi pumpkin into my 57 housing yet.
Then, there's the entire issue of Pontiac/Olds carriers and which gears bolt up to which carriers but that's a completely different subject.....

[rustynewyorker]

Yup, I had a few errors so I went to my source to clear things up:

Good info Rusty but I have to argue one point with ya. The rear axles from 57 and 58 both have only 29 splines, .....
Beleive they're 28, but either way it's fewer.
Pontiac didn't go to 31 spllines until '59 [neither did Olds!] and pontiac didn't offer a posi until '58. Actually there is a '57 Posi, it's just hard to find. I personally have seen a coiuple that must have had them in, too. That makes those '58 Posi's really valuable as it was a one-year option and they are the only year posi that will bolt into a leaf-spring 57 housing, using stock 57-58 axle shafts. Later pontiac axle shafts are too long and they're 31 spline.
Should be 57-58 Saf-T-trak
57-8 axles are 29 31/32" long
59-64 axles are 31 13/16"

If you slide a 59-64 posi 3rd member into your 57-58 narrow housing, expect to go looking for axles. I've tried using the 59-64 Olds 31 spline shafts as they're shorter than the same-year pontiacs [Wide track ride, remember?] and shortening them to work in the narrow 57 Pontiac housing but there's not very damn much splined shaft left after shortening.......I dunno about this shit..I may hafta bite the bullet and buy aftermarket axleshafts. This is correct. The guy who's explaining to me has been using Moser axles for several years but says Mark Williams also makes good pieces.

I'm told you need to grind on the early housing to fit the later posi 3rd member into it too.............I have one but haven't tried to bolt the '64 posi pumpkin into my 57 housing yet.
He says he's never had to grind the housings, but with some Dana Saf-T-Traks he's had to grind the axle ends to seat the wheel bearings - however on the Detroit Locker units he's never needed to do this.

Then, there's the entire issue of Pontiac/Olds carriers and which gears bolt up to which carriers but that's a completely different subject.....

Cut and paste he says:

NAW, THAT'S EASY. THERE ARE ONLY THREE (3) CARRIERS:

2-SERIES = 2.56 - 2.87
3-SERIES = 3.08 - 3.23
4-SERIES = 3.42 - 6.14

THE DIFFERENCE IS THE THICKNESS OF THE RING-GEAR FLANGE
AND OR THE THICKNESS OF THE RING GEAR ITSELF. IT VARIES
BY ~ .250" / SERIES. THUS, THE SPACER TO INTERCHANGE
BETWEEN/AMONG CARRIERS.

ANOTHER WAY TO LOOK AT IT IS BY THE RATIO. A 2.69 RATIO
R&P HAS 43 RING GEAR TEETH AND 16 PINION TEETH. A 4.56 RATIO
HAS 41 RING GEAR TEETH BUT ONLY 9 PINION TEETH. OBVIOUSLY,
THE 9-TOOTH PINION IS MUCH SMALLER IN DIAMETER THAN A
16-TOOTH PINION, SO THE RING GEAR HAS TO SIT CLOSER TO IT.
THUS THE SPACER (OR A "FAT" RING GEAR). IF YOU LOOK AT A
RICHMOND CATALOG, YOU'LL SEE THAT THEY OFFER BOTH THICK AND
THIN RING GEAR SETS FOR CHEVY 12-BOLTS FOR THE VERY SAME REASON.

http://www.richmondgear.com/01pdfs/page12.pdf <GM 9.3" TYPE C AXLE>

WHEN RICHMOND RAN 200 SETS OF 3.64's TWO YEARS AGO, THEY
DELIBERATELY MADE THE RING GEAR .250 THICKER, SO IT BOLTS
INTO A 3-SERIES CASE WITHOUT A SPACER. SPACERS DO NOT
HOLD UP UNDER THE RIGORS OF DRAG RACING. IF YOU WERE TO
SEE ONE OF THE NEW 3.64 R&P's, YOU WOULD IMMEDIATELY
NOTICE HOW THICK IT IS. THE REASONING WAS THAT 3-SERIES
CARRIERS ARE STILL PRETTY EASY TO COME BY, BUT 4-SERIES
ARE NOT. EVERYBODY HOARDS THEM...


Sorry on the caps - he uses them in replies so it's easy to tell what he wrote from what he's answering.

[new2u]

I know, I know digging up a post from wwaaayyy back....but I was searching google and found it so here goes

I've read the same and I've read different. Can anybody confirm or give more info? or pricing suggestions? I just picked one up today. offenhauser 2x4 #5029 fits 55-60 click here (http://hotroddersauctions.com/auctiondetails.php?id=100144)

Anymore info is appreciated

[1LOWCHIEF]

I know, I know digging up a post from wwaaayyy back....but I was searching google and found it so here goes


Holy crap there is a lot of good info in this post. Thanks for bringing it back.

[new2u]

Holy crap there is a lot of good info in this post. Thanks for bringing it back.Google :two thumbs up: I'm hoping somebody here knows a little more about this intake, at least more than I do! I wish it fit a chebby, I'd put it on the 'ol nova :D

[Brandy]

Google :two thumbs up: I'm hoping somebody here knows a little more about this intake, at least more than I do! I wish it fit a chebby, I'd put it on the 'ol nova :D

A NOVA? Oh you just hurt my feelings.:D