straight 8 flatheads

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exador

Well-known member
Joined
Feb 16, 2015
Messages
154
No reason for this but conversation and personal knowledge.

Do any of you run straight 8 flatheads?

No interest on fords.

For your choice do YOU KNOW if any speed parts are available for your motor? Prefer to know if you definitely know.

Any adapters or way to use a later 4sp. trans?

What influenced your decision.

Would any consider any of the old 12 cyls?
 
My future rat has a 350 chevy waiting for it as we speek , but Id love to find an old strait 8 or a 12 anything and put in it instead but , nothing like that is around here anymore ... My Dad used to have a 56 Buick Special with the strait 8 in it ,, wish we still had it ...
 
What particular flat straight 8s are you inquiring about? There were several. About the latest and probably the most common is going to be the Pontiac, used into the early 50s. And also the Hudson of the same vintage and they even came in a souped up version with twin carbs called "Twin H Power". Packard also used them into the early 50s. Any speed parts are going to be rare but if you scrounge far enough you might find a finned aluminum head for a Pontiac and maybe even a twin carb set up.
 
I've been hanging onto a 1949 Packard 288 straight 8 flathead that I took out of a 47 Packard I built a few years back. It was a good runner, I took it all apart and stored it in my shed for future use. I did do a complete porting job on it, opening the siamesed intake ports to 1 7/8" from the stock 1 1/2" and opening up the exhausts to 1 1/2", full pocket porting to smooth flow past the valves.
The plan is to get a rebuild kit from Egge Machine with .100 over pistons which will increase the displacement to 302 cu. in. I can have the cam reground with a performance grind and have the solid lifters refaced by Delta Cams in Oregon or Shadbolt Cams in Vancouver B.C.
It's possible to adapt a GM HEI to the stock distributor shaft or Pertronix makes a pointless module for the stock distributor.
Another upgrade that can really help is to re-plumb the oil pump (rebuilt ones available from Egge) to bypass the outlet to a full flow filter then feed it back into the mail oil gallery instead of the stock partial flow can filter. Another important thing to add is a PCV from the tappet cover to the carb instead of the old road draft tube - these two things will clean the oil better and keep contaminents out of the system, making a longer lasting engine.
Another idea for this engine is to swap in the longer stroke 327 Packard crank with the 288 rods - with a .100 overbore would bring it up to 347 cu. in. The longer 288 rods would move the piston pin higher and make for a lighter piston - though they would need to be custom made....
It's a trade off - the 288 should safely rev a little higher and quicker due to its shorter stroke but a larger displacement, longer stroke combo would make more torque. Either way, I don't think you'd want to turn it much over 4500 RPM.
I plan to make an equal runner length intake manifold from 2" exhaust tubing to mount a 600 Holley 4bbl. and build a set of headers - shorty small block Chev headers have almost the right port spacing - with a change to new flanges will make for an easy fit.
Edmunds did make intakes for this engine and a lot of other flathead 4 6 and 8 engines but are sooo rare (expensive!) and even finned aluminum heads but many of them really didn't flow that well or had casting flaws.
Bendtsens makes tranny adaptors for this engine to bolt on most any trans as well as adaptors for pretty much every vintage engine - if not they'll make one (also not cheap tho...)
Some day.... :cool:
 
I have a Pontiac straight 8 sitting in one of my 33's.
I love the sound that one make running and pulling. Shaamooth
I know it's not a flathead but, I'm eager to hear Bruno's Buick straight 8 run. Although, I don't think the zip tie idea will last very long on the header wraps [ddd
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I have a Pontiac straight 8 sitting in one of my 33's.
I love the sound that one make running and pulling. Shaamooth
I know it's not a flathead but, I'm eager to hear Bruno's Buick straight 8 run. Although, I don't think the zip tie idea will last very long on the header wraps [ddd


OI I have the stainless straps made for that purpose:D My health has improved so I've been piddling around in the garage some, nothing worth posting pics of yet.:( My grandpa had a 53 Pontiac, my dad has a 53 Buick and I had a 47 Buick, all were great running engines. Lots of torque but low rpm engines, little over 4000 on the Buicks.

PS, remember guys, if you smoke, STOP, COPD sucks!
 
The engine in Bruno's truck is cool beyond words.[cl There was a build going on here with a Pontiac flat head 6. Don't know what becaome of it.

zz's work on the Packard engine should make the project it goes in a real strong runner. I say we suggest he use it in his next project.[cl

I have a flat head Ford 6 I intend to put in the fourth project in by current build line up, if my old body holds up.

Reading Bruno's post above, maybe we should encourage Tripper to create a Health/Medical category.:D It could get more posts and any of the existing categories, based on the age and shape most of us are in.
 
I've been hanging onto a 1949 Packard 288 straight 8 flathead that I took out of a 47 Packard I built a few years back. It was a good runner, I took it all apart and stored it in my shed for future use. I did do a complete porting job on it, opening the siamesed intake ports to 1 7/8" from the stock 1 1/2" and opening up the exhausts to 1 1/2", full pocket porting to smooth flow past the valves.
The plan is to get a rebuild kit from Egge Machine with .100 over pistons which will increase the displacement to 302 cu. in. I can have the cam reground with a performance grind and have the solid lifters refaced by Delta Cams in Oregon or Shadbolt Cams in Vancouver B.C.
It's possible to adapt a GM HEI to the stock distributor shaft or Pertronix makes a pointless module for the stock distributor.
Another upgrade that can really help is to re-plumb the oil pump (rebuilt ones available from Egge) to bypass the outlet to a full flow filter then feed it back into the mail oil gallery instead of the stock partial flow can filter. Another important thing to add is a PCV from the tappet cover to the carb instead of the old road draft tube - these two things will clean the oil better and keep contaminents out of the system, making a longer lasting engine.
Another idea for this engine is to swap in the longer stroke 327 Packard crank with the 288 rods - with a .100 overbore would bring it up to 347 cu. in. The longer 288 rods would move the piston pin higher and make for a lighter piston - though they would need to be custom made....
It's a trade off - the 288 should safely rev a little higher and quicker due to its shorter stroke but a larger displacement, longer stroke combo would make more torque. Either way, I don't think you'd want to turn it much over 4500 RPM.
I plan to make an equal runner length intake manifold from 2" exhaust tubing to mount a 600 Holley 4bbl. and build a set of headers - shorty small block Chev headers have almost the right port spacing - with a change to new flanges will make for an easy fit.
Edmunds did make intakes for this engine and a lot of other flathead 4 6 and 8 engines but are sooo rare (expensive!) and even finned aluminum heads but many of them really didn't flow that well or had casting flaws.
Bendtsens makes tranny adaptors for this engine to bolt on most any trans as well as adaptors for pretty much every vintage engine - if not they'll make one (also not cheap tho...)
Some day.... :cool:

Great information. My buddy had a packard with the eight. Such a nice power train. My Dad ran a buick with an eight for a few years, plus two Hudsons.
Love the noises those cars made.
 
My Dad used to have a 56 Buick Special with the strait 8 in it ,, wish we still had it ...

Last year for the Buick straight 8 was 1953. Pontiac and Packard were the final holdouts, with 1954 being the final offering from both marques.

Speed parts are few and far between. Edmunds was the main producer for these engines, but they were geared more towards performance upgrades, not raw power (results definitely varied). "Speed" is also a loosely used term here, because straight 8's are anything but fast. They were produced for low RPM torque to move heavy luxury cars around smoothly and quietly. Of course you can improve upon them, but you better have some deep pockets if you expect any sort of performance. Transmissions adapters are available for any of them but again, be ready for some sticker shock...
 
Bendtsens adapter for the straight 8 Buick is $1,100 dollars. you get the 2 adapter plates, crankshaft adapter, flexplate for automatics, mini high torque starter and all necessary bolts. I'm running a 4 speed so I also got a flywheel from them. It is extremely well made and installed without any problems. I don't know what the cost is for the flat eights.

Looked it up...
Pontiac is $1,150
Packard is $900 to $1,100, guess they came in different sizes.
 
Stalled project

I was moving some stuff around in my shed and dug out my 49 Packard 288 cu.in straight 8. I did some porting to the block a few years ago, opening up the intakes - you can see the difference in the port size compared to the stock intake ports - need all the flow you can get with these siamesed intakes. I also started on building a 4bbl intake manifold to mount a Holley sideways, keeping the plenum small, intake runners to be 2" equal length tubes. I also made a saddle engine mount cradle to replace the goofy front mount that used to mount to the waterpump up high. This was a good running motor, just needing a 0.30 overbore and basic rebuilding to come back to life but that would be too boring....:cool:
I have a line on a 327 crank (1/2" longer stroke) that will drop right in but I would also need to use the shorter 327 rods. Stock 288 rods will work but will require custom made pistons with the pin 1/2" higher. This could be the best setup using a modern slipper type piston (lighter), better yet would be custom billet rods, since they are 8" long and the stockers are pretty spindly. The 327 crank is a beefy forged unit so the custom rods and pistons and balancing would make a 4500 RPM limit safe. I can still buy new lifters, valves etc and the cam can be sent out for a custom hi-po grind.
So, 327 crank and a 1/8" overbore (3.625 bore x 4.25 stroke) yields 350 cu.in. !! Now we're getting somewhere. The end of the line 1954 359 cu.in. Packard straight 8 made 202HP so it's reasonable to expect something like that output especially with improved intake, headers and hot rod cam.
No barn burner for sure, you could build two 400HP small block Chevys for what it may cost for parts and machine work but the coolness factor is way up there to me...
It has occurred to me that this would be perfect for my next 37 Packard coupe .... hmmmm....
 

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I wonder how that beast would sound with split exhaust... hmmm?

.

If you split the exhaust into 1,2,3,4 and 5,6,7,8 - small block Chevy block hugger headers have almost the right port spacing, just weld them to new flanges - you'll have a pretty normal 8 cyl sound.
However, if you arrange the pipes so they cylinders fire alternately into one collector then the other (180 degree firing) it will produce an entirely different sound, more like an Indy car (though obviously not revving that high) or an angry 6 cylinder.... 180 headers produce a broader, flatter torque curve which may play to strength of this kind of engine, not a revver but a puller.
Probably one of the most powerful flatheads made was the Hudson 308 six for one simple reason - it was one of the only inline flatheads I know of to use large individual ports for every valve. Flow matters and makes power. Even the Buick straight 8, though a new fangled overhead valve engine, used crummy twisted siamesed intake ports that severely limited flow.
 
Nine hundred & two....902 cu.inch.

V-12 Flathead @ Denver Fireman's Museum.

A Beauty. THIS would be my Rat Engine of choice ...just for looks.

Two spark plugs per cylinder; It's a slug/boat anchor, but beautiful close up.
 

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V-12 Flathead @ Denver Fireman's Museum.

A Beauty. THIS would be my Rat Engine of choice ...just for looks.

Two spark plugs per cylinder; It's a slug/boat anchor, but beautiful close up.

looks like an F head to me the exhaust exits out the top of the cylinder head, and the spark plugs are in the side of the head.

STILL, damn cool!!!
 

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