Packard Forum Index » Post-War (1946-54)

Good suggestion on reaching out to Ross and while I cannot say for certain the practice held with the 54 aluminum head, on the cast iron heads the number you see on the head is a casting number and not the actual part number. The part number was assigned after the heads were machined since the same casting could be machined differently for the various ratios or different arrangements of threaded holes on the side to attach other components.

The condition of the aluminum head won't be known till it is removed for inspection.

The correct part number for the 1954 359 cylinder head is 446974. The number on the head is a casting number, not a part number and the actual part number does not appear on the head itself. The Master Parts List identifies this head for chassis 5406, -13, -26, and -31 and notes a CR of 8.5/1. Though Packard promotional literature for 1954 models cited a CR of 8.7 for the 359 engine, there is speculation by quite a few that these engines in actual production struggled to achieve that; this may be supported by the parts list giving the CR as 8.5; dig around a bit and you'll find that quite a bit has been published on this years back.

On my own 1954 Patrician I never measured the cylinder head combustion chamber volume to calculate the actual CR, but I can say that even with the highest octane pump gasoline available to me at the time, preignition was a constant concern and annoyance.

Great, thank you everyone! Quick question. I've probably asked this before. I am finally in the process of putting in a new radiator. The original RAD is a 2.00 inch core LONG Mfg. The new one has a 2.25 inch core built to specs for a car with a/c. Unfortunately, the flanges on the new RAD that attach to the cradle were not centered at the correct ratio which cost me about 0.71 inches. All good though, with the rubber grommets all appears ok with the center bolts rigid. Back to the question, my 359 had a 160 degree thermostat in it and a 7 psi RAD cap. I am replacing with a 180 degree thermostat and a 13psi cap with the new radiator. Prior to me monkeying around, the car ran perfect and never over heated. My head is perfect. I've read about cracked aluminum heads. What actually caused the problems I've read about with Packard aluminum heads? Will I be ok with a 180 degree thermostat and 13 psi cap? Also, I tried to add a Flexalite fan but the one I had, the blade overhung the belts. Does anyone have the correct part # flexalite that might fit?

TC

My 1954 Patrician has a flex fan but will be removing it as it occasionally touches the radiator putting a light mark on it. Apparently the angle of the blades cause the whole blade to push forward slightly when I expected only the flex portions to move! Otherwise there is plenty of clearance.

Since it has a spacer and requires longer bolts to attach, the radiator must be removed first. It has been in the car for over forty years so I don’t know that the numbers are but I would not recommend installing one!

54packpac, (a) by today's standards those aluminum heads were of a relatively primitive alloy and they had similar failure rates with earlier Packards with aluminum heads, Hudsons, even Mopars in the 1980s, and (b) they were certainly not designed or intended to last 1/2 or 3/4 of a century. Even with the best of care, sooner or later they will all suffer failure.

Packpac, I've owned a '54 Convertible since 2005 with the aluminum head. In 2006 it looked like the head gasket blew (white smoke at the tailpipe and a burnt antifreeze odor) but it turned out that aluminum just crumbled around #1 cylinder allowing coolant to enter the cylinder. I took the head to a machine shop. They had the crumbled area rebuilt with aluminum weld and then they reground the area to spec. I put a thread insert into one spark plug hole as those threads gave way. It has been fine ever since.

Definitely go with the 13 # cap, just make sure it's the right neck length for the radiator. Mine had a 7# cap when purchased and it was dripping coolant when it was nowhere near overheating. The higher pressure cap took care of that.

Of course it's up to you but I wouldn't use a 180 thermostat. These engines generate a lot of heat as it is so I'd be leery of it overheating on a hot, humid day. The standard is 170 and low is 160. Before I realized the wrong pressure cap was on my car I put a 160 in. It didn't help the coolant purging but I left it in there after changing the cap and it works fine. I don't drive it much in the winter but when I do I get plenty of heat out of both the dash and under seat heaters. Good luck with your car.

Thanks again everyone for your input. My new radiator is finally in albeit flanges in wrong spot. Rubber grommets are in. All seems well. Temp gauge is right where its supposed to be. Today was 60 degrees outside though. 180 degree thermostat, 13psi rad cap, 20w-50 zrod oil, Hayden trans cooler and Zerex original green ethyl glycol. My fingers are crossed. Thoughts are welcome.

TC

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Check this out........

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That is a neat drawing of the cylinder head.....