600 CFM, all I need. Check my math!

Guys - Long story short. My 72 Plymouth Scamp (that was given to me) came with a brand new fuel pump and 750 cfm edelbrock (1407). As I got it roadworthy (Feb / Mar), and begin to spend money on it (exhaust), and test it at the strip (before improvements data), I find it is just as I suspected. I think it is running rich ... way rich. I'm going to *try* to tune the 1407 because within about a month I should have a whole new exhaust, including headers (versus oem manifolds). When I do the exhaust, I will put a clamp on bung on the exhaust and a wideband. I'll use the wideband to tune the 1407. I mean, I would just dump the 1407, but I'm going to try to tune it first. The 1407 was purchased new in November of 2016, and the only miles on it were from me, since February. Maybe 500 miles. So if I pull it, it will need a new home.

Anyway, from my math I figure several things. I want the car to run a 13.99999999 second quarter mile. After that, assuming the carb is tuned well, I will just drive the car and enjoy.

At 60 mph, it is turning ~3,000 rpm (727 / 8.75). The Scamp and I weigh in at about 3,210 pounds. Based on that, and using some "hp from ET" formulas to run a 13.99, I would hit the line at 107.8 mph.

Knowing the car is turning ~3,000 rpm at 60 mph (cruising, top gear), doing the math it should be turning 5,390 rpm at 107.8 mph.

Also, since the car is a 360, at 5,390 rpm, the engine would be consuming 561.4 CFM. I'll explain that below. But only requiring 561.4 CFM, a 600 CFM carb would be about perfect in size. No need for a big ole 750 CFM. I'm thinking the car would be faster and more efficient with a 600 CFM. Faster because it should produce better torque off the line with a better mixture from the 600 CFM.

Explanation (for those who care, and haven't done this themselves)

A V8 pulls in 4 intakes in 1 revolution. Which means it intakes 360 / 2 = 180 cubic inches of air per revolution.

Divide 180 by (12*12*12) to convert from cubic inches to cubic feet = .1041 cubic feet.

That is .1041 cubic feet per revolution.

Multiply that times 5,390 rpm = 561.4 CFM.



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