Projects 1956 Pontiac Gasser 389 swap (Finally Running)

At the risk of wearing you out............I got burned out on the entire old car scene around here. Go, park, sit 4-6 hours and cry when someone else wins the trophy. (I'm not interested in a trophy but when your vintage bike gets beat out by a brand new Can Am the scene is all played out).

So, I was going to sell my Pontiac.....but then I came back here and saw 55 Chieftan's build thread and got the itch to go another way. If it's no fun to park at least it should be fun to drive. (love the thread btw). I don't think I want to go that far but.......I have a 64 389 tri power readily available to me and a 4 speed. I also have (I hope) pedals and most everything else but smaller bits. The car as it now sits. I stripped the interior to re-do it and that will still be done.



The drivetrain came out of this car.



Not original to this car but important to note. The drivetrain from what I can tell (and this is where the questions start) I believe is out of a 1964 Catalina.





I was told that headers were not made for this particular engine. True? The Bonneville used to run on the track not far from here years ago. It comes with tri power (Edelbrock). I get all carbs but it was run with solid linkage. (all carbs operated at once). I'm assuming progressive linkage can be bought? (I have no desire to try and make some). (intake was plugged)



4 speed. The pedals out of the Bonneville........anyone know of problems putting them in the 56?



I don't have the garage space to do this. My buddy does BUT it's his livelyhood. I plan on using his space, his tools, etc so I do plan on providing him some $$$$$ so I would like to have my ducks in a row. (He wants the Bonneville body as partial $$$$)

Any pitfalls or things I should get before starting? I thought about full gasser but I'm not going to do it. The car is far from perfect but it is a fairly solid California car. I'm not going to cut it up. The suspension needs re-done though so it will sit nose high.

 

Can't help but looks like a nice project.

 

Partial payment ????? Damn.......hope the buddy does you one better then that. Those bodies are not too common to find. I only say that because I have lusted after a similar 421 powered hardtop racer for near two decades now.

Great project man. I hope to see no problems for you. Sending positive thoughts! Good luck.

 

The car is ate up bad. Remove the old bondo and it might blow away. Yes, it's a pretty rare car.

 

Yeah, if that '61 isn't a rust bucket, it's a pretty desirable unit. Pretty iffy on the pedal arrangement, might be easier to fab a whole new unit.

 

Problems with this swap:

55-58 Pontiac uses mounts at the motor's chin and at the bellhousing; you'll need to make new mounts for the side block mounts of the '64 engine. There aren't any kits out there, although some have been made in the past. You'll also have to make a trans crossmember with a mount, but those are usually fairly simple.

55-57 Pontiac have tight clearance on the steering and a master cylinder under the floor, so the factory ran the left manifold dump at the front and around the front of the motor to exit on the passenger side.

You can offset the engine an inch or two to the right to add clearance, try various headers and manifolds to see what will squeeze in, or it's not hard to put a 605 steering box in (bolts up and one hole lines up, IIRC) and change the column to something later to get around the manifolds. The master does not lend itself to conversion to dual chamber like say a 49-54 Chevy does.

I can't imagine the '61 pedals will work easily and they're likely worth a fair amount of money on their own - in fact you could probably sell that car whole for a decent sum, a '61 2-door hardtop 4-speed/manual trans car is if anything the more desirable of these two, even if it's rotted past your ability to fix someone out there is liable to build it. '61 cars should be hanging pedal while 55-57 pivot on the frame.

55-57 Pontiac manual pedals aren't that hard to come by, or you could change it to 55-'57 Chevy type hanging pedals, put the master on the firewall (move the defroster) and same a lot of hassle in the long run. Those would fit the car a lot more easily than the '61 stuff.

 

Oh, and on the carbs there probably is repro progressive linkage to be had, or you could just copy the factory setup.

As far as headers, any D-port Pontiac manifold or header will bolt up to the head, which leaves you a lot of options to figure out what might fit in there.

 

Boom POW !! RustyNewYorker is all over it! 4 speed 2 door hardtop Bonneville. Any year....hard to find. Agreed immensely so.

 

O.K. If a kit was made it would save a lot of effort. Not a major factor though.

Thanks.......I'll have to look into this.

Unfortunately the car is not a factory 4 speed. Started as an automatic.

I'm leaning this way. It would seem to cover a couple of my concerns. THANKS!

 

Great. Thanks!

 

I think you have an alternative for the motor mounts. The front timing cover for 1960 389 has the mounting ears that accommodate the front center mount....just like the 55-58s used and this can be adapted to your 64 389 if you care to pursue that....i.e. the mounting could be the same as the original 56....317 engine.....especially if you have the hardware from the 56 motor. Just a thought.

 

Will this work.......maybe not the ultimate but.......I don't really want to cut the car up. Get a steel front cover and mount the engine in the front. Crossmember in the rear.........

I'm looking and the passenger side manifold dumps at the rear. Will Super Duty manifolds (I believe there are aftermarket ones now) fit and could I run the passenger side on the drivers side and have it dump out front?

 

This is exactly what I was suggesting in the post just preceding yours here. The 1960 front cover is cast iron and has the lower mounting ears for the center front mounting but you will also need mounts back by the bellhousing, just like on the original setup w the 317 cube mill. Do you have the front motor mount from the original engine? The 60 front cover is the unit you should use as it doesn't have the reverse cooling flow setup of the earlier engines. The cooling setup is like your 64 389.

 

OK, I've done this swap a few times and also bought a 57 chieftain with a 67 firebird 400/4 speed installed. The best way is a total bolt-in operation. For this you'll need to find a 55-57 Pontiac with a manual tranny and harvest all [ALL] the pedals, linkage and any frame bracketry for the pedals. The Pontiac pedal setup is a complicated setup, totally unlike any 55-57 chevy pedal setup. [I cheated by starting with factory stick cars]
You could score a 59 or 60 block and a 58-60 stick bellhousing with the original 56 front motor mount and 55-57 rear bellhousing mounts. Your old 56 mounts will be borken, guaranteed so just spring for new ones.
The early bellhousing won't bolt up to a 61 block and to keep this deal a "bolt-in" you'll need that bellhousing because of the motor mounts on it.
Any modern chevy manual trans from 55 up including the T-5 will bolt up to this magical bell housing.
If you use the 61-up block, [and bell housing] you'll have to fab up a pair of side-mount brackets for the frame. Rodder's Digest has a killer article on how Gerry Burger did this very thing for his 55 tudor post including how he came up with a small rear crossmember to mount his muncie 4 speed trans to the front part of the X-member. [original 50s Pontiacs let the trans hang in the breeze..no support crossmember] He also used hanging pedals after patching the firewall hole for the defroster core. He also welded a strengthening plate into the firewall to bolt his pedals to. I think Gerry used a pair of 80s mustang pedals with cable operation but you should be able to science your 61 Pontiac pedals out ok.
DAMN! If your donor car was only one year older, it'd really make this entire operation easier.

 

Yes, I'll have the front mount. I'll figure this all out myself in the next couple weeks but I'm assuming a bellhousing for a 56 standard won't mount up to the 64? Did they make an adapter?

{edit} I see the post above that posted when I replied. THANKS!

 

No adapter I know of but a factory bellhousing for a 58-60 [stick] will bolt up to your modern trans and your original 56 motor mounts...however there are 2 bellhousing bolts that won't line up to the 61 and newer engine. I believe the '61 starter will work with a 58-60 bellhousing.[but it has to be a starter for a stick tranny...shorter than the automatic starter]
If you're going to use that 61 engine/bell housing, you're gonna need to fab up side-mount bracketry.

 

........and a 55-57 stick bell housing is only drilled/tapped for the early select-a-shift transmission...a piece-a-shit tranny at best.

 

Trouble is a 58-60 manual bell has become damn near unobtanium. For the time and money you'll spend to track one down, you could just fab mounts based on a later design - the 59-60 Pontiac motor mount takes one vertical bolt, similar to the Ford-type mounts a lot of kits use, so making a loop for it to bolt into isn't hard. Just use a cable throttle because when those break the motor lifts and a rod type linkage will jam, if you're not ready for it to hit the key and turn it off it will scare the crap out of you.... ask me how I know.

Supposedly there are two holes the front mount uses in the block which they stopped drilling after 1959, but different folks are finding different results.

By the way, '64 is a good block, it should have an ear for the block mounted starter although not all are drilled and not all drilled are tapped for the bolts. That lets you run later BOP bellhousing behind it - so you may want to check out that your manual setup is in fact '64 and not later.

 

I can't help but wonder if some home-built rear motor mount brackets could be fab'd up that bolt over the tranny mount ears, under the mounting bolt heads. That way a guy could make the brackets to accomodate early ford biscuit-type mounts with their thru-bolts, keeping the original 61 bellhousing and 56 trans mount crossmember. As for the super-duty manifolds......they're really expensive, even for the re-pops. I'm using a pair of old ram-air 3 manifolds, left manifold on the right side and right manifold on the left side. I did this to gain room for starter, clutch linkage steering box all on the left side of the car.
BTW, pictured is an extra bellhousing I have from a 57 GMC with a Pontiac engine. The flywheel mounts a 12 inch clutch. Has interesting rear motor mount bracketry that may be made to work on a Pontiac rear crossmember, I dunno. The rub is the GMC mounted the starter upside down....once again possibly interfering with exhaust, clutch linkage etc..

 

Thanks........I moved the 61 to "my garage" (the garage where we will do the work). (plans change.....61 will be for sale soon). I'll get the 56 there next week and hopefully disassembled by next weekend and plan from there.

I was told the 389 was freshened up not long before it was parked and I did hear it run 4-5 years ago but first things first and it will have to at least come partially apart to see what is what. Clutch disc had very, very little wear so.....

 

Its great to see a project that year other than a chevy ; nice.

 

Just for the helluvit I looked on one of the online Pontiac I.D. charts to see what "H" was. Uhhh, it appears anything with an H suffix is a 267 hp, 2 barrel 389 from 61 to 64 except AH which is a 1974, 400 engine. If you were hoping it was a super duty or "425A" 4 bolt main block, you'll be disappointed. Otherwise, all of the 2 bolt main blocks can be built up to make decent power.
That said, I'd love to see what that character is to the left side of the letter H on your block to help nail down the correct year. Also a cast number would help I.D. it. If it has bolt-up starter holes in the driver's side of the bottom of the block, it's pretty much gotta be a '64 and newer block..
BTW, just a plain "H with no letter or number associated with it means a 59, 389, 260 HP with a manual trans and 4 bbl. Cast number will narrow it down to correct engine.

 

Thanks Rocky....the book I have only shows 11H which is what this looks like as a 1964 catalina as you note 267 HP 389. No, I knew it wasn't a big HP 389.

Still, looks to maybe have been originally a standard that was listed as 267/410 with a two barrel as opposed to the 227/312 in it now. I have the three deuce intake and some other modifications I should be over 300hp and well over 400 lbs torque.

Not having unlimited funds I will be limited on exhaust options and probably need to upgrade the rear end to go over that anyway. I'll have more info the middle of the week. (having to work for a living sucks) I think I may have found a 59-60 Bellhousing. (anyone need a 64?)

 

I'm confused as to why you are interested in a 58-60 bellhousing if your engine is a 61 or later. Maybe I missed something somewhere along the line here. If you actually do need a 58-60 bellhousing and your "source" turns out to be a bust, I have one that I'm not going to be using.....JFYI.

 

I sort of need to see things go together to actually understand what I'm doing. LOL. The way I have this figured....
I can use the cast iron timing cover out of a 1960 to mount the 64 389 in the front (use the bracket already in my car) and use the 58-60 bellhousing to mount it in the back just like how the 56 drive train is currently mounted. The 64 4 speed will mount to the 58-60 bell housing. (see Rocky's posts).

Find a pedal and linkage out of a mid 50's Pontiac, cut a couple holes and it shouldn't be much of a big deal at all.

Right?????????

 

Right........except for one tiny detail. The 58-60 bell housing will only fit engines from 55 to 60. If using any engine/bellhousing newer than a 1960, you;ll need to come up with some way [other than the conventional 55-58 way] to mount the engine in your 56 chassis.. This is why I always use a 59-60 engine/bellhousing in these 55-58 chassis......no fabrication of any motor mount bracketry needed.
Poncho 60 has an extra bellhousing and if you can't come up with a 59-60 engine locally, I have a 59, 389.

 

Nothing like a '56 Pontiac, my first car. I put a 4 speed hydrostick in mine and used '57 Chevy powerglide trans mounts. A guy in town made mounts out of flat stock, welded to the frame for the outside part and cut the inners to fit the bellhousing. They worked well. Sounds like you have plenty of options. The original clutch linkage is a pain on those things. Never-the-less, sounds like fun.

 

Above you said that it would mount outside of two places. Close enough that you could drill and tap?

 

Probably not more complicated than the automatic........I figured that one out. Or is it? LOL