Optimum air speed and other dumb questions

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Daz570

Daz570

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Has anyone here done much research into optimum air speed for carburetor engines? I'm looking into a happy compromise between open ports and air speed on a smallblock I'm planning a rev range between 4000 and 7000 rpm.

For reference, each cylinder running around 35 cubes swept volume would require what cfm head flow to find a happy medium in your opinion
 
What is this engine being used for? What kind of racing? Does it need to have low speed performance? What induction? What exhaust header/system? How heavy is the car?
 
Car is around 1300kg (2866 lb) and going down

historic road rally car working within a rather restrictive class, 273ci plus whatever bore is required , around 880cfm carburession (slightly more metered than the average holley) 10.5 comp. limited to a torqueflite (but that's not all bad) aiming for a strong pull from 4000 to 7000 but to hold past 8 would be nice.
Between 3.45 and 3.89 final drive depending on the day
 
Actually,post:What are your expectations.Drivability?.Car weight,gears,transmission? Start with that,we need more info,epecially with a 273,sir.
 
Oops,walking dimbo!Touchy situation,what is allowed for head tweaking,sir?
 
What chasis is it going into? When you mean "anything prior to '72", that means available in Australia or anywhere? What exhaust manifolding are you considering?
 
The Class the car is being built around is replicating racing in Australia between 1965 and 1972, cars that have proof the make and model raced in the period are ellidgeable, most items that are free (carbs etc) had to have been available in this era.

The vehicle in question is a 1967 a body 4 door.
Exhaust, I was planning a custom set of open headers in time.
 
Gotcha. A lot depends on the package you run. I was thinking a typical set of iron 340/360 heads with a little work, and 1.88/1.65 valves. Depending on the cam choice and some other stuff you'll need around 230cfm of intake flow to make peak power at 7800. Also bear in mind - this engine is not a really wide power band engine. So you'll want to be careful with rear axle ratios and transmission type. I don;t think a torqueflite is what would be best. I think a manual trans would be better.
 
A 1967 would be a VC Regal V8 then.

They showed some of the old footage from Bathurst back in the day and there was a clip with what looked like a black VC Regal V8 leading at 1 point.

Hysteric
 
[ame="http://www.youtube.com/watch?v=8RdmlZUAU8Q"]http://www.youtube.com/watch?v=8RdmlZUAU8Q[/ame]

I would imagine the ap5 is a slant 6 too!

Hysteric
 
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