CALCULATING WITH AUTOMOTIVE FORMULAS

STATIC COMPRESSION RATIO = cylinder volume + chamber volume + gasket thickness volume divided by chamber volume and CC’s in piston dish. Since this is usually figured in CC’s inches must be multiplied by 2.54 for conversion. So 563.46 + 52 + 2 = 617.46cc divided by 52cc + 13cc = 65cc or 617.46 divided by 65 = 9.5 -1 STATIC compression ratio.

DYNAMIC COMPRESSION RATIO = calculated off internet at “RB Racing” = 7.43 or 8.3 to 1 depending on the cam and when the Intake Valve closes. IC @ 65 degrees = 7.43 to 1 or IC @ 48 degrees = 8.3 to 1.

DISPLACEMENT = ¼ of pi x bore squared x stroke x number of cylinders = engine cubic inches. So we have .7854 x 13.99 x 3.13 x 6 = 206.35 cu. in. after the .060” overbore.

CYLINDER VOLUME = ¼ of pi x bore squared x stroke = .7854 x 90.2424 x 7.95 = 563.46cc

THEORETICAL CFM NEEDED FOR RPM = rpm x cubic inches of motor divided by 3456. So 3000 rpm x 206 cu. In. = 178.82 cfm needed. That is approximately 80 mph. The 1100 “big” carb is rated at 185 cfm. For a maximum rpm of 4000 = 238.43 cfm is needed. Top-end would be better but daily driving would suffer. The 1100 AUTOLITE carb. cfm rating was taken off the CLASSIC INLINES site using the 1.20” venture version. That is the Mustang carb used on the 200” six, found originally on full size Fords.

RPM AT GIVEN MPH = mph x gear ratio x 336 – divided by tire diameter. So 80 mph x 2.83 gears = 226.4 x 336 = 76070.4 divided by 25.5” tire diameter = 2983 RPM. This engine can easily run over 4000 rpm.

MPH AT GIVEN RPM = rpm x tire diameter divided by gear ratio x 336. So 70 mph = 2625 rpm / 75 mph = 2800 rpm / 80 mph = 2983 rpm / 85 mph = 3170 rpm / 90 mph = 3356 rpm / 100 mph = 3729 rpm.

STATED STOCK HORSE POWER/TORQUE = 120 HP @ 4400 rpm / 190 ft. lbs. TRQ. @ 2400 rpm. With the modifications about 20 HP and 25 ft. lbs. torque have been gained for 140 HP/215 TRQ. Due to slightly higher compression 89 octane gasoline should be used to avoid detonation.

WEIGHTS & BALANCE = Title weight of the six cylinder Mustang is 2600 lbs. It has about a 54% to 46% front to rear weight ratio while the V8 is approx. 58% to 42% F to R, plus the V8 model adds about 300 lbs. overall. The V8 and its engine parts are about 100/110 lbs. more than a six, V8 suspension, brakes, driveline and steering parts add another 180/200 lbs. Together that equals 280 to 310 extra pounds or two 155 lb. friends in the back seat eating nachos!

This engine should be able to run past 100 mph since road tests from 1965 showed 90 to 99 mph as top speed with a smaller carburetor, more restrictive exhaust, six fewer cubic inches and milder ignition. This engine has more HP/TRQ. a cool-air intake and cruises easy at 70/75 mph getting 24/25 mpg. It should be able to pull 4200 RPM and 110 mph is only 4102 RPM. Weight, fuel, engine tune, wind drag and road conditions make a difference but an HONEST 110 MPH should be achievable…under the right conditions. NO it will not outrun a modern V6 with fuel injection, but they are not 50 years old operating with half-century old engineering! This engine has ZERO electronics!

All the above data was calculated using AUTOMOTIVE ENGINEERING FORMULAS and honest numbers. If estimates were used they were conservative.

 

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