Packard Forum Index » V-8 (1955-56)

Greetings, Men-Who-Own-One,

In another thread someone mentioned the possibility of late-56 engines being made up of the sweepings from the parts bins. We do a lot of 374" and naturally, these are later build engines.

On a couple of performance engines we have in progress just now, I note three different manufacturers of connecting rods. "Atlas" is the only one identified by name. These also have cast-in Atlas 8, Atlas 9 and Atlas 10, all in one engine set.

Working with these mixed sets of rods is a royal pain, because they are widely varying in weight. There is a balance pad left on the forging on the top and bottom of the rods. On some rods, the balance pad is virgin; no grinding for balance at all. On others, the balance pad is almost ground away.

When doing a performance balance, all components to less than a gram variance, we're finding for all their bragging, Packard was pretty sloppy with static balance.

We've got six more 374" cores on hand. Maybe the easiest way is to pull all them down, sort out the rods, and try to make sets from the same forging foundry and re-number them.

Question: on '55 engines, is it more likely all rods in a given engine would be from one manufacturer?

Question Two: One P/N for 352" and 374" crankshafts. Anyone know differently? The 374" pistons are 38 grams heavier than the 352" pistons. We balance most of our engines, but what about the dealer ordering a replacement crankshaft? They definitely didn't rebalance, so which crank did Packard ship and did they have vibration problems as a result?

thnx, jack vines

What about 352 rods???? Have u seen the same type of variations in the 352 rods??? I have a 352 seting here i can check the rods for a name. Where on the rod is the name "Atlas" ????

"On a couple of performance engines we have in progress just now, I note three different manufacturers of connecting rods. "Atlas" is the only one identified by name. These also have cast-in Atlas 8, Atlas 9 and Atlas 10, all in one engine set."

So then, there is at LEAST 4our different rods???
Atlas 8, 9 and 10 make 3 different rods and at least one more not cast with "Atlas" make 4.




Seems to me that there is an STB or SC that indicates a different crank for the 56 Carib.

I do not understand question 2 at all.

If there is ONE, exactly one and only one part number for 56 v8's then there is only one crank that the warehouse could ship.

55 V8 cranks are identified by a "4" on the front counterweight for the 1955 352 V8's. A "3" for the 320 V8.

With the crank REMOVED from the engine how well is the stock crank balanced????

"We do a lot of 374" and naturally, these are later build engines."

Do u have any explanation on why they are LATE 56 V8's?????

Thus far i have found only 2wo different rods in 5672a-1834 engine. One rod is 'smooth' but has a SLIGHT hip at the yellow horizontal marks. The other rod has no hip but has a slite raised ridge along the length of the rod as noted in the other pic between the yellow VERTICLE lines.

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