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How about just milling the head and using a better carb or carbs?

According to Turnquist the limit on milling is .045 for the eight and .007 for the V-12.

And those numbers are only useful if you know how much the head(s) might have been previously milled. Absent that, sometimes you can "cc" the combustion chamber if you can find the OEM spec; otherwise I use the modeling clay or putty on the top of the valve heads to judge how much clearance remains.

No the number Turnquist refers to is the absolute limit from standard. .045 for the 8 and .007 for the V-12 are the discard limits.

Tim, I think we're saying the same thing. I'm saying that you just can't pick up a used head and assume it hasn't been surfaced before so knowing the limit is only useful if you know the prior history.

The point is: not going to work.

So are there any trick to get a few more horsepower out of a 29 engine? Will this intake help?

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All of this discussion is great. Nice manifold Dan.

Tim, twice now you have simply stated it isn't going to happen or won't work. Can you please explain. You obviously know something significant about these engines so please share. Cheers Mal

Dear Mal:

Be happy to. The kernal of the issue is: can 14th series motor parts be bolted onto a 6th series crankcase to turn it into a 130 horsepower engine?

The camshaft is different, as is the block (according to the parts book the 14th series gasket is different), the crankshaft is not the same, and you can't mill cylinder heads because the gasket seal will be eliminated.

Now for people considering milling a head as part of a rebuild, very carefully evaluate the issue using a machinist grade straight edge and a feeler gauge. The standard is generally .001 for a cylinder, .004 for an entire head, and .002 for 6 inches. However, the Packard head may allow a little leeway in that .004 could be used for four cylinders. And if there is no indication of leakage then don't cut it down. Also, store the head on it's side. Don't leave it thrown in the back seat, trunk, leaning against the wall, etc. etc..

The 6th series uses a double disk clutch and so the transmission is another problem.

I don't know if the 14th series crank would actually drop into the 6th crankcase, but the whole motor was changed for the 7th series so I couldn't imagine that it would. One thing is in writing from Packard - Insert rods was not authorized for 6th series and earlier cars.

Another problem is the crankshaft itself. After all these years they are not very strong. They bend easily. The wise old timers generally took it easy on these cars and did very well. The cowboy's blew them up.

I'm not much of a hot rodder mainly because the cheapest modern cars will outperform most of the so called American muscle. However, most of these Packards have seen so much use that the build quality has been worn out of them, thus no inhibition towards doing something else with them.

Tim, thank you for your explanation of the differences between 6th and 14th series std 8 engines. It certainly does seem there are a lot of differences and not worth pursuing interchaging parts of the motor. Is there anything that can be done to the 6th series std 8 to increase the HP or should it be rebuilt to standard? Maybe the best way for me to go is to use the complete 14th series motor (and try to find a 14th transmission if the 6th series tranny wont bolt on)and modify the engine mounts to suit the chassis. This way I get a later motor with more HP and still looking 'vintage'.

Dan, that twin carb and straight exhaust namifold looks great. What engine is it on, and has it been running? Love to know more about it and the car it is in. Cheers Mal