Packard Forum Index » Modification Discussion

What are the head milling numbers and chamber re-contours for best performance to increase performance of the 1949 straight 8? There are several books out on the Ford V8 flathead modificatons for increased power-unshroud the valves, notch the block, etc. Phred

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G'day Phread,
to PackardInfo. Sorry, can't help with your query. Eric, this might be up your alley? Presume you have a '49 Packard and if so invite you to include it in the Owner Registry together with a pic, any known history and how you acquired it

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I have a few ideas, send me a PM.

My 1949 Packard is the 4 dr touring sedan model w/Super 8 (327). The amount that I can mill the head on this engine to realize the power/economy on the octane now available (89-92) that was originally engineered by Packard is my goal. On flathead 6 cyl Studebaker Lark you can remove as much as 0.60" from the head for max. performance. Seems like 0.40" would be a reasonable number on the 8 cyl. flathead Packards. I would need to check valve head clearance before starting it up on the off chance that there is a clearance issue. I do not think an aluminum head was ever manufactured to fit this post war engine.

Un shrouding the valves, i.e. like on Ford flatheads, is an optiion but you will loose some compression ratio numbers(increased head combustion volume)but the air flow number increase should more than make up for that. Did Packard or a privateer ever run a straight 8 engine at Bonneville or on a track in modified form to set any speed records? If so, those modifications would have been captured in old SAE papers of the time. Phred

There are plenty of folks out there who have milled a Packard head 0.030" and bent the valves as they hit the head because they failed to consider if the head had been previously milled. And then you can be in a real pickle, new heads are rare, and double-gasketing or useing extra thick custom head gaskets doesn't usually work for long.

What's wrong with leaving it stock?

Ths stock compression ratio was optimized for 87 max octane fuelafter WWll.Increased compression is the easiest way to improve performance/economy of an engine. I will consider a valve head-to-combustion chamber roof clearance measurement to baseline the factory numbers. This engine has a very well documented history from the original owner so this will guide me to work up to a number for material removal on the head sealing surface for a daily driver. Phred

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Pull the head, get some clay and put it on top of the valves. Turn the engine over several times, then pull the head. Measure the thickness of the clay to find out the clearance between the head and the valve. Simple as that.

Another solution, and one I approve, but if you go too far it will lower the c/r, and that is to polish the combustion chamber in the head. I plan on doing this on the head on the Speedster, as it will get rid of possible hot spots caused by casting flash. I'm not too worried about compression, as I plan on forced induction. (along with larger valves that will probably require clearance grinding anyway)

instead of shaving the head why dont you fill up the combustion chamber over the pistons since you already know it's flat? weld and mill.

Quick and easy, just find a head from a 53 or 54. Give it a light cut to clean it up and then polish up the chambers a bit with a roloc wheel. That will give you a hair over 8:1 so you can still run regular no sweat with Packard's latest and best effort at combustion chamber design. Try to get a 53 or 54 327 distributor to use with it as they give more advance. (The 359 distributor only works with the aluminum head.)

If you are taking the engine all apart, by all means get a cheap die grinder and clean up all the bumps and stalagtites in the ports. Round off the edges of the angled pockets that the valves sit in--no need to cut a channel all the way over to the cylinder in my opinion. But be sure to stay away from the area the head gasket touches! I do this on all my rebuilds and the owners are thrilled with the change it makes for an hour's labor.

Keep in mind that almost all Packards with high mileage are in need of rings and this will do far more for a tired engine than any cylinder head. Very often the top rings are broken.

Consumer Reports described a 53 Clipper with 327 and overdrive as "excessively powered" Yes Please.

G'day all, I have been through the mill with modifications to 327 Packards since the late 1960's and what works for me, currently fitted to my 1938 120, with R6 overdrive is:.......
1:...... Use a 288 head on the 327 as it has a combustion space of 109 cc Versus 137cc for the 327. It will raise the comp ratio from 8:1 to 8:5 to one without modification. I have also taken 100 thou from the 288 head and I am running close to 9:1 ratio. I am fortunate that a side valve has increased turbulance at the inlet valve and therefore a lower Octane requirement.
2:..... Bore the engine out to max. I have bored the 327 out 60 thou and it is close to 340 Cubic inch.
3:.... Fit a free flow carb and exhaust. I am running a Holley 600 and a 2.5 inch exhaust with a hot dog as the muffler.
It certainly is not the final word on grunt but it wants to wheelspin in second gear on a wet road like it is the final word.
Best Regards Peter Toet