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I have two identical cylinder heads one says just Packard and one says Packard HC. I have a 40 120 which I need to r and r the head.
Can anyone tell me if I can use the HC head. thanks

G'day fogfather,
to PackardInfo. Shouldn't have any issues using the HC head, it only raises the compression ratio about 1/2 a point, and was routinely used back in the day. What you'll need to look for is whether it's been machined at some time in it's life, and if so, is valve clearance still OK?

And, here's where I get up close and personal, I invite you to include your '40 120 in the Packard Owner's Registry here on PackardInfo!

thanks that helps

I had the head planed so what should I do to check the valve clearance. Perhaps measure the clearance somehow?

That was quick work, for including your '40 One-Twenty 4-Door Touring Sedan in the Registry. But I have to ask, is your Packard possibly this one? There aren't too many white Packards around.

The question on how to check clearances I'll leave for the more experienced and knowledgeable to advise on.

If the head really needed to be resurfaced, you should determine the clearance BEFORE you have the head surfaced as you probably don't know if it's been resurfaced before and if so, how much. If insufficient clearance is left, the head is junk. If you use the search function and browse around you'll find quite a few posts on how to measure the clearance, but a quick and dirty GO-NO GO test is to put the head on the engine with a used headgasket, and DO NOT install any head nuts. Crank the engine over with the starter motor and carefully watch the head for any movement. If there is ANY, the valves are hitting the head - you have insufficient clearance and need to find another head. The disadvantage of this method is that it shows if there is clearance, but not how much - it could still be very marginal so quantitative methods are better.

It might be the same car but I obtained it from someone in El MOnte. I am out of town for a while so I can not check. Thanks for the HEADS up

Reason I asked is that I met the owner and saw that car when I was in the US in 2007 buying my '41 Coupe. Much as I've always done, and there are others here who will attest to this, invited myself along to meet Ron and see his Packard!

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Dear fog:

I would use the HC head given the antiknock quality in today's 90/10 gasoline.

If the head needed to be planed that should have been checked prior to the procedure using a calibrated straight edge. Anyway, the head should be stored on its side.

So... the way to check clearance is to buy some strip caulk at the local auto supply and roll it out to around .060 on the bench. Put some inside the head, lay it on the motor,
crank it over by hand using the flywheel. Take the head back off and check for contact with the putty. You can measure interference that way.

Hope this helps