Patrick, if there was a displacement rule and a cylinder head rule, then you could opt for a shorter stroke. Sometimes we favor an oversquare situation because the larger bore will take advantage of the cylinder head/valve size.
AL, you have to be completely blind (or just have too much pride to admit it) to ignore the fact that there are 5.5" stroke engines that run at 9000 rpm.
Again, you can NOT use generalizations when speaking of engines.
Cobra Make, Engine: ERA #732, 428FE (447 CID), TKO600, Solid Flat Tappet Cam, Tons of Aluminum
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No, no rule limitations involved. If you believe the answer is that there is never a reason that a skilled FE builder would opt for a 4.125" stroke (other than a race class restriction rule of some sort) then you should say so. Is a rule limitation the only time you can think of?
In a street car, I would rather have the cubes. I don't know why anyone would logically settle for a smaller stroke when the longer stroke rotating assemblies cost exactly the same.
In a race car, I would rather have the cubes. Pat Musi builds Mountain Motor class Pro Stock engines. They are 903-1000 cubic inch engines. They turn very high rpms and they are very undersquare.
In roundy-round applications such as dirt track racing, common engine sizes are 427-434 cubic inches. These engines turn 8000-9000 rpm, with the largest stroke they can fit in the block due to piston height constraints. These are applications where they require on/off switch style engine response. The stroke doesn't hinder that.
Jay Brown builds FE SOHC engines. He keeps increasing the stroke and I believe is up to a 4.600" stroke with a custom billet crank. He's approaching 8000 rpm with this engine and doesn't he use it in his Drag Week car?
I think we all may not still be on the same common ground as far as terminology and what's going through our minds. I'm still confused on whether we are comparing equal engines, or if we are comparing "potentials." I also think that some people's judgment may have been clouded by low compression, short cammed truck engines with 50 lb flywheels.
... AL, you have to be completely blind (or just have too much pride to admit it) to ignore the fact that there are 5.5" stroke engines that run at 9000 rpm.
Again, you can NOT use generalizations when speaking of engines.
But I can use generalizations as most cobra enthusiasts do not buy super trick builds costing upwards of $30K and more. What does that 5.5" stroker that revs to 9000 RPM cost? Better yet, what are the chances there is a member here with such a motor, slim and none.
That's been your problem with this debate all along, you fail to see that for the common enthusiast, certain general rules do apply and are totally applicable to the motors they consider for these cars. They are not exotic limited production builds that you continually reference as your "examples", that's just nuts, no one here uses them in these cars.
Here's the general reality for the guys that want to keep it reasonable in the motor department, and what they consider when making their decisions. Bore to Stroke Ratio & Other Design Concerns
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But I can use generalizations as most cobra enthusiasts do not buy super trick builds costing upwards of $30K and more. What does that 5.5" stroker that revs to 9000 RPM cost? Better yet, what are the chances there is a member here with such a motor, slim and none.
That's been your problem with this debate all along, you fail to see that for the common enthusiast, certain general rules do apply and are totally applicable to the motors they consider for these cars. They are not exotic limited production builds that you continually reference as your "examples", that's just nuts, no one here uses them in these cars.
Here's the general reality for the guys that want to keep it reasonable in the motor department, and what they consider when making their decisions. Bore to Stroke Ratio & Other Design Concerns
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This discussion has not been about money, and you're well aware of that. Here, have another straw....
This discussion has been about your need to troll each thread that involves talking about crankshaft stroke, and inserting your completely incorrect generalizations.
And BTW, we all know that racier parts cost more. Did you end up using that Superlight crankshaft that you listed for your engine? If you want to talk about staying reasonable in the engine department, I would make the argument that you don't spend $1200 for a Superlight crankshaft in a low rpm, low compression street motor.
But I can use generalizations as most cobra enthusiasts do not buy super trick builds costing upwards of $30K and more. What does that 5.5" stroker that revs to 9000 RPM cost? Better yet, what are the chances there is a member here with such a motor, slim and none.
It's not mine, but my good friend has put this 5.7" stroke motor into his street car. Sounds like it revs just fine for a pump gas street engine
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