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

I get to drive lots of Packards in my business, and I have always felt that there was something a little special about the 54s. Clippers and Cavaliers always seemed to have more snap and be more responsive than the equivalent 53s. I was hard pressed to believe that the 5 hp difference between equivalent engines could be that noticable--and wondered also where that 5 hp came from.

There were only two basic cams supplied for the 288/327 family, either hydraulic lifter or solid lifter flavors. Even the cam for the 359 has the same timing as a 327 (per the specs in the back of the service manual), but I understand it is notched a bit for conrod clearance. Thus it gets a different part number.

Anyway, I just noticed that all the 54s other than the 288 got a new cam gear. This must be indexed differently than the old cam gear. With the old gear the intakes started to open 15 degree BTDC, with the new, at 10 degree. All of the specs are shifted the same 5 degrees.

I'd love to hear some comments from folks who know cams about the whys and hows of this change. Apparently it helped the breathing on the big engines. Wouldn't it also help the 288? I'm just building up a 288 now for my roadster and would make a stepped drive key to achieve the 54 timing if it seemed a good idea.

That's real interesting, Ross, never noted it before. I did just browse the 54 Salesman's Data Book and see a single comment on page 63 that "The valve timing on the 165 and 185 h.p. Thunderbolt engines has been changed to deliver greater horsepower and increased engine smoothness."

That is something to ponder Ross. I know they made small tweaks to the motors through the 51-54 years. The most evident is the rise in compression ratio year over year, which I have been looking at lately.

This is because at some point in my car's history someone replaced the 1954 327 Head with a 1951 288 head. Which does have me a bit concerned because of the lower compression ratio of the 1951 288 head over the 1954 288 head. But I guess we shall see how she runs when I finally get her started to see if I need to shop for new head or not.

Cam timing is an interesting subject. By advancing the cam you get better cylinder filling at low speeds, retarding the cam gives better cylinder filling at high speeds.

By advancing or retarding the cam you can "rock" the torque curve about its midpoint.

Stock car racers used to take advantage of this. They were forced to use a stock cam, back when there were no factory performance cams, but by advancing or retarding the cam could get more power where they wanted it.

And about the cylinder head. The exact same head will give a higher compression ratio on a 327 than on a 288. Because the cylinder volume is larger in comparison to the head volume. So your 288 head will have more compression on your motor than on the original 288.

Whether it is more than the stock head, I do not know.

Thanks, Rusty, that was just the insight I was looking for. I am guessing they left the 288 alone so as not hurt its low speed torque. With that relatively short stroke it does not have that in the abundance the 327s did. With that in mind, I think I will just dial in my cam timing to the stock 15 degrees before TDC. But the next time I build a 327...

They make offset keys and offset bushings for adjusting cam timing.

Here is a simple trick. Try advancing the cam to different degrees and check compression with a compression gauge. Whatever setting gives the most compression will give the best low speed power.

This is handy to know when installing a hot cam if you don't want to kill your idle and low speed power.