Packard Forum Index » V-8 (1955-56)

Howdy fellas. I’m getting ready to begin a rebuild on my ‘55 400 352 V8. (See my project blog.) To begin, we’re rebuilding the engine and I’m wanting to do a few mild upgrades, enough to hopefully hit 300 horsepower.

My current ideas are:

Use the heads off of my 352 from 1956 (Purchased, but haven’t pulled them from the spare engine yet)

Stick with the ‘55 4 bbl. intake (Already have from the original engine)

Put a Holley 4 barrel on, ported to 650 cfm (Already purchased)

Port and polish (Can purchase the tool at my place of employment for $52)

Use the ‘56 camshaft and have a mild performance ground done (Purchased, but haven’t pulled it out of the spare engine yet.)

Jack Vines oil pump conversion (Need to purchase)

I do not want to bore it out unless absolutely necessary.

I also want to swap my ‘55 Ultramatic to a ‘56 version. I have lined up to buy a core ‘56 transmission along with the torque converter from Mike Dulinski.

My question is, what else will I need? Can I use my ‘55 linkages? Are the mounts different? Does everything just bolt up? Etc.

I would appreciate advice on the engine also. I plan on purchasing the Egge kit that comes with practically everything except the cam and crank. This will be my first engine and transmission rebuild, however I have my dad and grandpa who are incredibly experienced with building them, so I’m hoping for the best! I’d like to hear any tips and pointers you all have for the rebuild process itself also! Hoping to have everything done by this summer so I can be the only 21 year old cruising down the road in a 400 in all of West Virginia!

Thanks in advance everyone,

Deven Vance

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Others can get more detail.

But the trans was not designed for high. Horse power.

The 56 carribean used a different pump in torque converter.

And different valve body.

For higher horse power.

Best to contact Ross Miller. Get his input.

PM him.

The shift points are different on 55. The 56 has L R H D P.N.

THE 55 has those triangles between gear shift. On steering .

The 56 trans will not need any different linkages or mounts and will just bolt in place of the 55. The only visible difference is the 56 unit is a bit smoother appearing and several pounds lighter because the case is aluminum instead of cast iron.

It sounds as if you are going for a bit more performance with your engine rebuild. As Riki says, the trans was NOT designed for high horsepower and to go farther, the trans turned out to be for all practical purposes the weak spot in the 55-6 Packard lines. Basically, the Ultramatic was a very early automatic designed entirely in house around a straight eight engine that averaged around 165 hp and less than 300 ft/lbs of torque. Unlike competitive units that came into use for other mfgs 55-6 models, it did not have the benefit of hindsight, collaborative production or high volume experience when for competitive reasons it was hurriedly modified and then bolted onto a V8 engine whose output averaged considerably more at around 250hp and 350 ft/lbs.

With the mechanical components being almost identical but engine output increasing a substantial amount, that along with some teething issues with the many hydraulic changes needed to make essentially a single speed non shifting transmission with torque multiplication into an actual two speed gear shifting unit with torque multiplication things started to give and transmission issues were numerous. For 56 they revised and refined what they could in the valve body to minimize the harsh and runaway shifts but the mechanical limitations were still essentially unchanged even though engine power was increased even more.

To sum it up, the Ultra will perform adequately and for the most part reliably if driven sedately or with some decorum but if you plan on fast getaways from the stop light to take full advantage of a high horsepower engine or if you find yourself in driving conditions that require a lot of up or down shifts you may soon be reduced to limping home or worst case suffer the indignity of calling a car hauler to be carried home.

That's exactly what I wanted to do when I was your age, albiet more than fifty years ago. I'm finally able to build them.

As to ordering a kit from Egge (or Kanter, et al), be aware there are several key parts currently NLA.

If one wants Packard V8 horsepower, by far the most cost-effective place to start is with a 374" block and order custom pistons .125" oversize with modern thinner rings. We've got core blocks available.

Line hone and square deck the block; balance the rotating assembly.

We have a custom reground camshaft which will take advantage of the extra inches.

Absolutely necessary to remove the soft plugs at the ends of the rocker shafts and clean inside with a bore brush and solvent. Then, regrind the rocker tips. We have rebuilt units on the shelf.

Install removable valve guides in the heads and use positive valve stem seals.

Why a Holley carb? It will require an adapter to bolt to the Packard intake. The Edelbrock has the matching base bolt pattern and will be fine for your use.

Your build, your budget, your decisions. Let us know what we can do to help.

jack vines

Quote:

Im not going for an ultra performance rebuild, just a few extra horsepower. Definitely not a race car or anything, but able to keep up with highway traffic, although highway driving will be rare. I’m thinking 300 maximum, before the power steering, generator, etc is added. With just mild daily driving with the occasional quick get away, do you think it’d be decently reliable? I’m considering going the GM 700r4 route but at the same time I’d like to get the experience of rebuilding Ultramatics, and maybe one day become the “go-to” contact for rebuilding them. Thank you for all the info! Excited to hear back again

Quote:

What parts are unavailable from Egge? Are there other sources? I’ve heard mixed things about Kanter in regards to engine parts so I’m kinda afraid to order from them. How do the plugs come out? Are they pressed in? Also, the Holley is because I already have one from grandpa’s stash of parts. Freshly rebuilt it and it’s ready to go. I’m not exactly looking for a high performance build, just a reliable, peppy daily driver quality build. 300 Hp MAX before power steering, generator, etc. Do you think a ‘56 Ultramatic would be able to handle that, with just mild daily driving, occasional highway cruises, and the rare quick get away? Thanks for all the great advice and help so far and looking forward to hearing more!

Zipping off the line is hard on the valve bodies
.
One guy was racing burned up the valve bodies. Goes back to the 60s

I've done mods. Look at my blog.

If you want more power go dual quad.
.
Keep the 352 cause Pistons are available

The trans can be reliable if it is babied provided it is gone thru and thoroughly inspected with all worn or questionable parts replaced. Ross can guide on that with his videos on YouTube and has also developed a couple of mods that seems to help the shift points to make the transmission more pleasurable to drive. IMO, It will never have the easy service and parts availability or performance and reliability of a correctly installed 700R4 if you are looking for a daily driver type situation.

One of the bigger downsides of having a Twin Ultra is that unless you plan on doing the work yourself, if a problem arises there are almost no local trans shops that will even consider taking on a repair job. Even among those Packard people who still work on them, the really knowledgeable service is limited to one or two people on each coast with NOS parts similarly constrained to one or two vendors. Ultramatic seems to be a bad word so of the few local shops that deal with older trans that might be willing to talk to you the Ultra, being a unique unit with different operating principles and characteristics or foibles other trans of the era did not share, is an anomaly. The mechanic might be a Hydramatic or TorqueFlite expert but unless he is is also very familiar with a comparatively rare Ultramatic he can miss something or worse, can do real damage to the unit. In that scenario any repair $$ will be wasted and you might be looking for a new unit.