Cylinder heads:
240 heads have a 68cc combustion chamber.
300 heads up to 1986 have a 76cc combustion chamber.
1987 and later heads have a 68cc heart shaped combustion chamber. These are the EFI heads

Heads up to 1984 have stud mount rocker arms with slot shaped pushrod holes in the head to act as pushrod guides.
Up to 1977 the 3/8" rocker studs used a 3/8 x 24 self locking adjusting nut.
The 1978 to 1984 heads use a shouldered 3/8 positive stop rocker stud with a 5/16" x 24 nut with no adjustment. The nut is torqued to the stud shoulder.

1985 and 1986 carburetor heads and 1987 and later EFI heads have pedestal mount rocker arms with round holes in the head for the pushrods.
1984 and earlier heads use a 4.810” long valve while the 1985 and later carburetor and EFI heads use a shorter 4.750” valve.
All have 11/32” valve stem diameter, 1.780" intake diameter and 1.559" exhaust diameter

Here are stock replacement retainers for use with the Comp 903 spring.
55-6179 | QualFast High Performance Retainer | Goodson Tools & Supplies

If the head is converted to screw-in rocker studs then the SBC 4.910” long valve can be used for oversize valve installation as well as the SI 4.810" long Ford 300 1.94"/1.60" valves.
The 1985 and later heads will need pushrod guide plates when converting from pedestal to stud mount rocker arms.
The following ARP studs have the longest adjuster thread and are short at 1.75" length.

7/16 studs:
ARP 135-7101, 180,000 psi tensile strength
ARP 235-7201, 200,000 psi tensile strength

3/8 studs:
ARP 134-7101, 180,000 psi tensile strength
ARP 234-7201, 200.000 psi tensile strength

Chevy 250 six and Big Block Chevy rocker arms can be used with the screw-in studs.
However please note that the Ford 240/300 spacing from the rocker stud center to the valve tip center is typically 1.59" which makes the BBF and BBC 1.650" length rockers long and ideal rocker geometry can not be achieved and rocker roller tip travel is nearly quadrupled.
The Harland Sharp roller rockers have the correct length at just under 1.600" and provide the correct rocker geometry as does the Chevy six rockers.
Scorpion 1059 are 1.73 ratio pedestal mount roller rockers for the Ford 300 six. They are a direct bolt-on for the 1985 and later heads

The EFI heads with the heart shaped chambers promote swirl and are considered "fast burn".
These heads require less ignition timing as a result and should yield better fuel economy.
However because of the valve shrouding the heads flow less than the earlier 300 large chamber heads below .350" valve lift.

Piston and connecting rods:
The 240 rod length is specified at 6.7947” and the 300 rod is 6.2097”. They are generally rounded up to 6.8" and 6.21"
The 1965-1968 240 and 300 rods have a .912” wrist pin diameter. 1969 and later rods have a .975” pin and an oil spit hole in the big end of the rod.
All rods are .992” wide at the big and small end.
Rod journals are 2.123”

Crankshafts.
The 240/300 light truck and car crankshafts are cast iron.
The F600 truck and some of the industrial engines used forged steel crankshafts.
There are 2 forging numbers for the 300 forged crankshaft.
The 4 digit prefixes are
C5TE
C6TE
The next 4 numbers are the base part number and the last letter is the revision level.


240/300 block deck height is 10.00”
240 stroke is 3.18” and 300 stroke is 3.98”
Standard bore is 4.00" for all blocks.
Rotating assemblies will interchange between the 240 and 300 blocks.

A favorite combination is to use the longer 240 rod on the 300 crank.
This allows for a shorter and much lighter piston along with a higher rod length to stroke ratio.
The .912” pin rods allows the use of Ford 302 and 351W V8 pistons.
The .975” pin rods for 352 and 390 Ford FE V8 pistons.

The small 2.100” journal BBC rods have a .992” wide big end can be used with custom pistons.
These rods use the SBC 2.100" bearings.
The 300 crank rod journals are turned down from 2.123" to 2.100" to accommodate the BBC small journal rods.
The 6.385” long small journal BBC rod is available as an “off the shelf” item.

This connecting rod is ideal for power adder application.
Molnar now makes a heavy duty "H" beam connecting rod specifically for the Ford 300 six.

The 240/300 lifter is .875" and is common throughout the Ford six and V8 engine families.

The cam bearing housing bore on the Ford 300 engines manufactured after June 4th, 1985 was changed to make production installation quicker.
Previously all four housing bores measured 2.1440.
The late style block with the casting number E1TE-6015AA, has the following cam bearing housing bore dimensions:
Location Part # Bore Diameter
1 E5TZ-6261A 2.1590
2 E5TZ-6262A 2.1440
3 E5TZ-6262A 2.1440
4 E5TZ-6261A 2.1590

There are two main thrust bearings. A 3.567" OD flange and 3.602" OD bearing flange.

For those that want to build a very high rpm 240 including turbocharging where the rpm is only limited by the valve train.
Molnar makes a 7.130" long billet rod for the Chevy 292 six that will fit the 240 crank.
The 240 crank journals are turned down to 2.100" and the journals are widened .035" so a generous radius can be formed for extra crank strength.
https://www.12bolt.com/store/p32/292...et_Molnar.html



Use a custom forged piston that has a 1.28" CD with a total piston and pin weight under 600 grams and have a screaming six.

 

This is the classic long rod 300 build using the 240 connecting rod with the 300 crank.

The plan was to produce 325 hp at 5500 rpm. Unfurtunately I moved from WA state before having the opportunity to dyno the engine.
The owner reports plenty of torque from 1200 rpm and 18 mpg @ 70 mph highway (2400 rpm) and 15 around town. 1977 2wd pickup, T18 tranny.

I will try to keep this post compact by using links instead of imbedded pictures.

Addition block prep included removal of sand/iron lumps and pockets in the crankcase.
Grind away all casting lines including the cam tunnel and main webs.
https://www.dropbox.com/s/s6u3h61cke7kf0v/IMG_0026.jpg?raw=1
https://www.dropbox.com/s/qjh45e9hdbtd2ro/IMG_0027.jpg?raw=1

Lunatic Fringe added the very nice porting of the oil passages in the filter mount that's not included on this engine.
https://fordsix.com/viewtopic.php?p=613172#p613172

The 1985 carb head had Chevy 2.02" intake and 1.60" exhaust valves, 4.910" length along with porting.

Combustion chambers were finished out to 77cc
https://www.dropbox.com/s/hoxt81l1paszfrs/Upright%20intake%20port.JPG?raw=1
https://www.dropbox.com/s/pycdq6q58ecd0v0/Exhaust%20Port.jpg?raw=1
https://www.dropbox.com/s/5t7b6y8h5vdpuk0/Chamber.JPG?raw=1

Heads were drilled and tapped for 7/16" rocker studs.

Comp 1826-12, 1.6 ratio roller rockers

The head valve spring seats were machined to fit Comp 994-12 double valve springs. Installed height 1.665"

.530" metal clad Viton valve seals.

Adjustable pushrod guild plates were welded on a 1.940" center.
https://www.dropbox.com/s/hw9cogn2posft0c/Guide%20Plate%20Fixture2.JPG?raw=1

Manton 4 Series 5/16" x .118 wall, 10.290" long pushrods.

1965-1968 240 connecting rods forging number C5AE
Polished, shot peened and resized with ARP rod bolts.

AutoTec 4.040" pistons, 1.190" pin height, .912" pins and 10cc round dish. 9.75 compression ratio.
Piston and pin weight reduced from stock 819 grams to 574 grams.

BWE zero gap rings
https://www.dropbox.com/s/h5rwpzcctzeewvb/DSC01558.JPG?raw=1
https://www.dropbox.com/s/k9u6bhvzw0p5w1b/IMG_0010.jpg?raw=1

Jones Cam, Hydraulic F300-I6, H72334, L/C 112
232/232 .050" duration, 288/288 advertised duration, .534" valve lift. 112 LSA
Jones J875H lifters

Clifford intake manifold with Quick Fuel HR-650 carb. (I preffer the new Offenhauser 4 barrel intake but at that time I found the used Clifford manifold cheap)

Hedman headers
MSD 6AL ignition

Sitting on the run-in stand waiting for the Manton pushrods and MSD coil. Break in with outer valve springs only.
https://www.dropbox.com/s/h5jmi733n0q96je/IMG_0136.JPG?raw=1

 

Engine Dimensions for installation.

 

Please add this thread to the Sticky thread section

 

Will the intake manifold on a 300 fit a 240? I believe the answer is yes but wanted to validate with experts.

 

Yes
Even the EFI intake manifold from the 1987 to 1996 EFI engine will fit the 240 head.

 

Wow! that is cool. did not know. I am rebuilding the 240 now. do you recommend putting the EFI on instead of the manifold with the one-barrel carb?

 

I recommend using the EFI exhaust manifolds only.
If you do decide to retrofit the Ford EFI you would have to use the EFI head to get the correct burn rate for the EFI computer. Also, there it no place on the 240 block to mount the knock sensor.

 

You can use the EFI intake manifold if you use an aftermarket EFI system.

 

Dear All:

Hopefully this hasn't been dealt with before. Regarding the 1994 4.9L EFI head: What are the flush "plugs" with the large female inset hexes in the head next to each rocker arm? No manual talks about them. I was curious about inserting a large hex key and turning them out.

Thanx,
BSI