Formula Ford Engine Specs
(From Vara)

                                                                     

A. General

The Formula Ford engine shall be the standard Ford 1600cc pushrod crossflow, as installed in the following vehicles:

Original version- Cortina 1600 through 1970 model
Uprated version- Cortina GT (1971), Capri (1971), Pinto (1971)

Components shall not be interchanged from the original and uprated versions of the engine unless specifically authorized. Regulations pertain to both versions unless otherwise stated. Original Ford Motor Company replacement parts must be used unless otherwise specified. The engine shall not be altered, modified, or changed in any respect, unless specifically stated herein. Balancing of all moving parts of the engine is permitted provided that such balancing does not remove more material than is necessary to achieve such balance. It is permitted to polish parts of the engine provided the contour of the part is not altered and can be recognized as the original part. Maximum compression ratio: Original engine 10.0 to 1 Uprated engine 9.3 to 1.

The following specs are used in determining compression ratio:

Uprated 1.33 cc- top ring to top of piston -.33 cc- volume of valve protrusion
Original 1.64 cc- top ring to top of piston Both engs 4.75cc- head gasket

Minimum unswept volume per cylinder:

Original engine with std pistons- 44.4 cc
Original engine with +.030” pistons- 45.1 cc
Uprated engine with std pistons- 48.2 cc

B. BLOCK

Bore may be enlarged to increase clearance between piston and cylinder. Cylinder liners may be fitted. The top surface of the block may be milled to obtain the maximum compression ratio, as specified above. Any steel center main bearing cap is permitted. The 1600 Pinto block, DIFZ-6010C, may be used as a replacement for the Cortina GT block. The Fiesta block may also be used as a replacement

C. CYLINDER HEAD

Ports may be reshaped by the removal of metal as long the port diameter at the manifold face of the head does not exceed the following:

Inlet 1.50”
Exhaust 1.16”
Combustion chamber (original engine only)
Minimum depth .115”
Maximum length 3.15”
Minimum volume per cylinder 7.8 cc
Reshaping is prohibited A standard dimension head gasket shall be used. Head gaskets may be exchanged between the original and uprated engines. (See Miscellaneous, S.2.b) The use of the Pierce aluminum cylinder head, as approved by SCCA is permitted.

D. INLET MANIFOLD

The ports may be reshaped by the removal of metal as long as the following dimensions are maintained.
Max size at head face:
Original Eng Uprated Eng
cyl 1 & 4 1.48 x 1.28” 1.24”
cyl 2 & 3 1.25” 1.25”
Max size at carb flange 3.060 x 1.389” Max length 3.80”
Primary choke end radius .709”
Secondary choke end radius .787”
The carb face of the inlet manifold may be machined to the horizontal to compensate for fore/aft tilt of the engine
The water passages in the inlet manifold may be plugged

E. PISTONS

Standard, .015 oversize, and .030 oversize may be used in the original engine. Only standard size pistons may be used in the uprated engine. Ford or Hepolite cast pistons may be used. The new CP ff1600 forged piston as sourced by Jay Ivey of Ivey Engines is also allowed. Mahle pistons are not allowed.

Maximum diameter: Standard 3.189” Original and Uprated Eng
.015 OS 3.204 Not permitted – Uprated engine
.030 OS 3.219 Not permitted – Uprated engine
Depth of bowl (+/-.005”) .500”
Max dia of bowl 2.28”
Min vol of bowl 31.50 cc
Centerline of wristpin to crown 1.737 +/-.002”
Overall height 3.30”
Min weight with rings and pin 515 grams
Weight of pin 115 +/- 2 grams
Piston rings are unrestricted provided that:
(i) One oil control and two compression rings are used.
(ii) No modification is made to the piston for the installation of rings.
Pocketing of the piston valve relief’s is allowed up to a maximum of .050” to obtain minimum combustion chamber volume.

F. VALVES

Original eng Uprated eng
Distance apart at centers 1.540 +/-.020”
Max dia Inlet 1.502” 1.560”
Max dia Exhaust 1.252” 1.340”
Overall length Inlet 4.280 +/- .006” 4.367 +/- .020”
Overall length Exhaust 4.260 +/- .006” 4.355 +/- .020”

Reshaping of the valve is specifically prohibited (single 43-47 degree seat angle only).

G. CAMSHAFT

The camshaft lobe profile shall not be altered. The following specs are provided for checking only.
Lobes, heel to toe Inlet 1.280-1.322” max
Exhaust 1.280-1.323” max
Lobes, base circle radius Inlet .540”
Exhaust .545”
Lift at top of pushrod Inlet .231 + .002” max
Exhaust .232 + .002”max
Lift at spring cap Inlet .356” max
(with zero tappet setting) Exhaust .358” max
Recontouring of the valve stem contact pad of the rocker arm is permitted, provided the maximum lift at the spring cap is not exceeded.
Offset camshaft/ sprocket dowels/ buttons are permitted.
A camshaft that is a replica of the original camshaft and of the same material and is dimensionally identical may be used. A camshaft meeting this requirement, as approved by SCCA, is currently produced by Elgin Industries.

H. VALVE SPRINGS

Valve springs and valve spring shims are free except:
(i) No more than one spring per valve
(ii) The standard spring cap and retainer must be used
(iii) Springs shall be made of steel

I. PUSHRODS

Minimum stem dia .25”
Overall length 7.64” Minimum
Minimum weight 50 grams

J. CONNECTING RODS

Minimum weight: Both engines: 630 grams
(Note: Weight includes cap, bolts, and small end bush, but not big end bearing shells.)

K. CRANKSHAFT

Weight: Original and Uprated engine 22lbs 8oz Minimum
Stroke at piston 3.056 +/- .004”
Crankshaft pulley unrestricted Either crankshaft may be used in either engine.
The crankshaft may be shot peened. The use of an aftermarket crankshaft of the same material, weight, and profile as the original is permitted. 

L. FLYWHEEL

Weight with ring gear and dowels: 15.5lbs minimum (either engine)
The flywheel may be machined provided the machining to reduce weight to the above minimum weight retains the standard profile.
Alternate flywheel from JAE P/N JAE1600 is also allowed, to the above weight of 15.5 lbs

M. CARBURATOR

Weber 32DFM, 32DFD, 32/36DGV, Holley 5200
Venturi diameter: Primary- 26mm, Secondary- 27mm

Permitted modifications:

1. The fitting of any jets (incl accelerator pump discharge nozzle), which may be fitted without modification to the carburetor body.
2. Modification or substitution of external throttle linkage.
3. The fitting of internal and/or external anti surge pipes.
4. The removal of the air cleaner.
5. The fitting of a velocity stack.
6. The fitting of any filtration device directly to the carburetor. No scoops, snorkels, or ram air devices unless original.
7. Removal of the choke butterflies and linkage.
8. An alternate carburetor gasket is permitted provided it is the same thickness as the original.

N. FUEL PUMP

Unrestricted

O. EXHAUST MANIFOLD

Unrestricted- except exhaust outlet must not extend more than 60 cm (23.6”) behind the centerline of the rear axle.

P. OIL PUMP AND SUMP

Unrestricted- dry sump system is permitted.

Q. COOLING SYSTEM

Radiator, fan, water pump, and drive belt unrestricted.

R. ELECTRICAL SYSTEM

Distributors are unrestricted in Formula Ford, provided the original drive location and housing (standard Motorcraft/Autolite, Lucas, or Bosch) are retained. The distributor is defined as the component that triggers the LT current AND distributes the HT current. The ignition timing may only be varied by vacuum and or mechanical means. It is prohibited to use any other method or component to trigger, distribute, or time the ignition. The vacuum advance mechanism may be removed, and the distributor advance plate may be secured by soldering, welding, or suitable fasteners. The advance curve and springs are unrestricted. Generator/ alternator not required.
Transistorized/ electronic ignition is prohibited.

S. MISCELLANEOUS

1. The timing chain/sprocket cover may be altered or replaced.
2. The use of the following nonstandard replacement parts is permitted provided their use does not result in any unauthorized modification to any other component.
a. fasteners (nuts, bolts, screws, studs, etc.)
b. Gaskets made by manufacturers other than Ford may be used provided the head gasket, carb to inlet manifold, and inlet manifold to head gaskets are identical dimensions to the Ford standard parts.
c. Washers
d. Seals
e. Connecting rod bearings, crankshaft bearings, and camshaft bearings of the same size and type. Normal over/under size bearings are permitted. This does not allow reducing the bearing surface area by reducing the width of standard bearing.
f. Rocker pedestals are allowed of any materials but must be dimensionally identical (i.e. shaft location, offset, etc.) to the original components.
3. Mechanical tach drive is permitted.
4. The crankcase breather may be altered or removed.
5. The rocker cover may be altered to provide for crankcase ventilation, and the filler cap may be altered or replaced.
6. The crankshaft and main bearing caps may be treated with salt bath or gas nitriding as covered by SAE spec AMS2755A (tuftriding, etc)
7. Water pump, fan, and generator/ alternator pully (s) are unrestricted.