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Re: Dual intake for thunderbolt
#11
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Ross
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Here is a fascinating movie from Hudson, the first I have ever encountered. Thanks Youtube!

youtu.be/x9kJ76U9Hc4

In it is described the difference between power and torque, but also is hinted what mods Hudson made for increased performance on their flatties. Couple of things to note--how relieving the block and a very briefly mentioned LD (long duration) cam flattened their torque curve so it did not drop off so fast at higher engine speeds, which is the curse of flathead engines as they struggle to breathe.

Note also as the staggering combinations of engines, heads, and carbs are rattled off and compared with Hudson's 53 engines: The optional aluminum heads offered only a few extra horsepower. The dual carb setup about 10. Most of their gains over 53 came from their "Super Induction" modifications, ie the cam and relieving.

Also, if you google "port and relieve flathead" you will find more info than you can look through in an evening.

Posted on: 2013/4/2 6:12
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Re: Dual intake for thunderbolt
#12
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Owen_Dyneto
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Ross, thanks for posting that, very interesting. IIRC from my Hudson drag-racing days, 1954 was the first year that Hudson gave a factory-advertised horsepower to their Hornet 308 engine with Twin-H carburetion. The Twin-H setup was 2 Carter WA-1 single barrel carbs rather than a single 2-bbl. I believe the single 2-bbl was rated at 160 hp and Twin-H at 170 but the 170 rating was very conservative, thus giving Hudson some of their NASCAR advantage. The 1954 Hornet 308 was the 7D engine but a 7H version was available to the racing guys with a hot cam (#311040?), aluminum head, split exhaust manifold, and really importantly an increase in the head stud size from 7/16 to 1/2 inch. This was really important because when repeatedly pushed to the max they had a tendency to blow headgaskets. On our 54 7D, we often blew a headgasket every weekend. The block on those Hudson engines was of a very high nickel content cast iron and were very difficult to bore; generally they had to be ground to oversizes. Another interesting feature of many Hudsons was that they used pinned piston rings though we abandoned that when we rebored. All of the Hudson 6-cylinder engines of that era from the Jet (202 ci), Pacemaker (232 ci), Wasp (262 ci) and Hornet (308) shared the same design concepts and were real torquers - our primary competition at the strip was from the early Olds V8s and we dusted them off with regularity. But if the 1/4 mile had been 50 feet longer I doubt we would have.

These details are a little hazy, it was about 50 years ago, so someone correct me if I've got some of it incorrectly.

Posted on: 2013/4/2 8:47
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Re: Dual intake for thunderbolt
#13
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David Grubbs
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for what it's worth, when I had my 288 engine rebuilt two years ago, I had Delta Camshaft inTacoma WA do the work. They put a mild street grind on it, and parkerrized it to harden the metal. You do need to tell them if you will be using solid or hydraulic lifters.

I was quite please with the work, and they were reasonable. The engine runs just a bit rougher at idle than a stock cam, but it does have an improved low end torque. Plus I've found that feeding it non-ethynol premium really perks it up. In MT, Chevron and Exxon premium doesn't have alcohol in it.

Posted on: 2013/4/2 10:05
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Re: Dual intake for thunderbolt
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steve-52/200
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I am looking forward to a 327 hydrolic lifter 8 cyl rebuild ,I will install a 288 head ,a 2 2bbl carb set up this is pretty standard stuff I hear ,I will have the cam reground a bit to handle the breathing improvement ; ,BUT in this thread some one mentioned 288 rods ! this is a new wrinkle what gives ? I will be getting a rebuild kit of parts so nows the time to go for it !
what about welding a plate on the top of the stock exhause to use with he dual intake

Posted on: 2013/4/7 1:37
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Re: Dual intake for thunderbolt
#15
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David Grubbs
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The 288 and 327 have the same bore and cylinder size. The rods on a 288 are shorter than the 327's. I made my 288 into a 327 by installing the rods and crank from a 327 with a cracked block. I used the 327 cam and had a mild street grind put on it. You also have to use the 327 damper. Let us know how the dual carb works out. My fellow old car mechanic who drives Hudsons has a theory that the dual carb setup helps prevent vapor lock. He has several Hudsons, some with the dual carb and some with the single carb and swears that the dual versions don't vapor lock nearly as much. Plus it looks cooler!

Posted on: 2013/4/7 8:33
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Re: Dual intake for thunderbolt
#16
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Anthony Pallett
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David you have your rod lengths backwards the 288 had a shorter stroke with a longer rod the 327 had a longer stroke with a shorter rod they used the different rod length to enable the use of the same piston. So with the use of a custom piston with the proper pin height and the longer rod on a 327 you get a Better rod stroke ratio. Its the same basic concept as going from a 5.7 rod to a 6.0 rod in a small block Chevy. the science can get a bit in depth but the longer rod makes the piston dwell a bit longer at TDC and the rod itself doesn't whip around as much. Its a minor improvement at the power levels and RPMs the L8 Packard will be at but the way I look at it every bit helps.

Posted on: 2013/4/8 12:45
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Re: Dual intake for thunderbolt
#17
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steve-52/200
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so when its rebuild time ,if I put a 288 head on the 327 to bump the compression just a hair ,and i order a rebuild kit for the 327, will the rods that come in the kit be ok?

Posted on: 2013/4/16 23:52
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Re: Dual intake for thunderbolt
#18
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Tobs
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All The rebuild kits I have Seen (for packard) don't come with new rods. You'll have to use your own old rods. Might also want to check that they are straight and balance them.

Posted on: 2013/4/17 4:07
1953 Clipper Delux Club Sedan, 1953 Caribbean, 1969 912, 1990 Miata
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Re: Dual intake for thunderbolt
#19
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Anthony Pallett
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Yes for sure balance them. Do a bit of research on your local shops to make sure you find one that knows what they are doing. Ideally you should have the whole rotating assembly balanced as in pistons rods and crank it will make the engine smoother and a lot more reliable in the long run. You might even pick up some power.

Posted on: 2013/4/24 14:46
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