Found it:

https://packardinfo.com/xoops/html/downloads/Packard%20Heads%20Compression%20Ratios.pdf

There is a post here somewhere that lists all the 288/327 heads and the different compression ratios when swapped to different blocks.

One of the heads I have has something like 288STD 327.

Quote:

Yes to the puller. On a 55 the wheel needs to come off and after unplugging wires to turn signal sw etc and loosening or removing clamps and disconnecting linkage plus removing the toe board the outer column and shroud will slide up and off the shaft. You might want to note the gap distance between wheel and column upper shroud before anything comes apart so as to make reinstallation less of a guess. There is also a split concave ring around the shaft that forms part of the upper bearing that may need to come off before the column will slide up the shaft. If you are able to slide it up without removing the ring be sure to keep track of it because the ring must go back on for the bearing to work.

55s had the old box with full length one piece steering shaft so the shaft is integral with the steering box and will remain. You will probably have enough room to tilt the dash out a bit but if it looks to stress the shaft and becomes absolutely necessary you can remove bolts and loosen another at the steering box so the box will tilt and shaft can drop down slightly. I never tried it but there might be enough play in loosening the steering box bolts you could get enough lowering of column without removing it or the wheel. Need to really protect column from scratches though and you will probably find the wheel will be a pain to work around.

56 models had the short column and stub shaft connection to steering box so that column is easily removed in its entirety with minimal disconnections without touching the wheel.

My 327 has a 288 head on it as well. Slight compression ratio bump.

Now we know why those rotary antennas are so hard to find. They were back then also, as Packard lost it's supplier.

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The heads were physically interchangeable but with slightly different compression ratios so once you determine which engine you have, you can then find which engine is needed. I do have a 1951 300 core at my Oregon shop should you need it.

Thanks. On my Clipper all the front of firewall wiring just except the foot switch is already disconnected but not so on my 400. Likewise for the Bowden cables... for various reasons they're all already disconnected on the Clipper. So looks like the only thing "in the way" is the steering column needs removed which I assume requires a wheel puller etc.

You could also have a stuck ring. I had that issue when I first got the Clipper running. I poured in some Lucas Oil Stabilizer and went for a 150-mile drive at interstate speed. When I got back, the problem had disappeared.

Also:

46P-40 AUTOMATIC WINDSHIELD WASHER
49P-35 BACKUP LIGHT EQUIPMENT FOR 23RD SERIES ULTRAMATIC CARS
50P-44 ROTARY ANTENNA - 22ND AND 23RD SERIES CARS