Mitch it is good to hear further updates on your fine 56 Poncho. I like the thought of dropping a 400 Pontiac motor in her. Those were incredible engines that Pontiac put out, tons of torque. Continued good luck on your sweet 56 Poncho. As you know photos are always an appreciated must by the Pontiac brotherhood here. Cheers. George.

gnipgnop wrote:

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Photo update showing the breakdown of my original 1956 Pontiac rear axle (top) and the donor 1955 Chevy rear axle I picked up at a swap meet (bottom).  The intent is to use the best parts from both for the rebuild.  

My '56 Pontiac rear-end has original axles with a 3.73 (R41-P11) gear ratio.  The '55 Chevy rear-end came with new axles and 3.08 gears (R37-P12). I noticed that the carrier from the '55 Chevy has the extended gussets on the differential bearing mount which makes me think it may be a carrier from a '57.

The axle tube and spring perches on the '55 rear-end are damaged, so the plan is to clean-up and re-use my original axle housing and install the new axles and the '57 carrier with the 3.08 gears.  I think the 3.73 might be a bit too tall of a gear for the TH350 and 25" tall tires I plan to run.

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 Mitch i think the 3.08 might be a far better idea, especially if you plan on doing highway cruising and are not Bill Gates in the wealth department. The 3.08 is an excellent "gas wise" idea. On the other hand if stop light or drag racing screaming is what you are looking for, then the 3.73 should do good by you. Thanks for the updates on that fine ride of yours. Please keep the brothers posted. Cheers. George.

gnipgnop wrote:

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Update on rear-end rebuild:

-New axles, bearing and seals

-Sandblasted, primed and painted:  axle housing, brake drums, carrier housing, backing plate, leaf springs, shackles and u-bolts,

-Rebuilt brakes, new brake lines and emergency brake cable

-New leaf spring bushings

 

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Excellent! Still on my 'to-do' list is building my original 56 rear end - I bought a new Auburn Positraction and new Motive 4.11 R&P (designed to fit in the 3-series carrier) and Ratech complete installation kit (bearings, seals, shims, crush sleeves, etc.), but I was planning to use the original axles ... any reason why you decided to go with new axles?

Thanks,

Dave

btw I have tall rear tires and I am aiming towards a Hot Rod and I don't care if I am 3,000+ rpm on the highway.

2" dropped spindles, upper and lower tubular control arms, coil springs and shocks installed. 

I decided to cut off 3/4 of a coil from the front springs to try and compensate for the eventual lighter front end weight created by some of the modifications such as aluminum engine components, aluminum radiator, trunk mounted battery, lighter control arms, etc (approx 200lb reduction).  Combined with the 2" dropped spindles, I hope my guesstimate doesn't put me too low in the front (fingers crossed). 

gnipgnop wrote:

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Installation of the rear shock relocation kit.  It relocates the top shock mount from the body to a frame mounted cross-bar.

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 I just recently did this over the winter on my 57 Pontiac. Mine looks a bit different than yours. I would recomend this mod to any one that is not building a museum piece kind of car. This is obviously what Chevrolet should have done in the first place. Well worth the minor cost and effort for a better ride and more quite ride. Continued good luck with your fine 56 ride. Cheers. George.

gnipgnop wrote:

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  Combined with the 2" dropped spindles,

I hope my guesstimate doesn't put me too low in the front (fingers crossed). 

 

 

 

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         Sometimes LOW is good  lol lol lol