Given the fact that the same questions come up repeatedly and we frequently have to ask the same people for the same answers (viz. "what do my casting numbers mean?"), it's been decided that a Big Six FAQ is in order.
Q: how can I tell the difference between a 240 and a 300?
A: If the Head is off the best way is to measure the Stroke Length a 240 has a Stroke of "3.18".
The 300 Six has a stroke "3.98"
Or you could also put a stiff wire or long Screw driver down the #1 Spark Plug Hole at TDC make a mark there on your wire or screw driver and then turn crank to BTDC make another mark now measure the distance from the two marks and compare to the above measurements to get your Stroke Length.
Another way is to look at the Design Casting Numbers on the Block and the Head. Original Engines would be decoded like this
A 240 engine would have these Prefix Number and Letters I believe that Fords first use for the 240 Six was in the Big Ford Cars their first year of this Design Code is C5AE-6015-A
C = 1960
5 = Is the year added to the above gives you 1965
A = The Ford division that ordered that Part be made is, A = The big Ford Car Model Line
E = The Division that made the Part = Ford Engine Foundry
6015 = Ford's Generic Part Number for a Bare Engine Block it will be the same for any Ford Engine Block
A = Is for the Design Changes in this case its for a First Year Part.
These 240 engines were also used in the 1965 Ford Pick Ups but they will still have that AE in their Design numbers on their blocks and Heads.
The 300 Six also came out in 1965 but it was designed for use in the Ford Pick Up's and Ford never officially installed them in the Big Ford Cars for sale to the public.
C = 1960
5 = 1965
T = The Ford Truck Division
E = The Ford Engine Foundry
6015 = Ford's Generic Part Number for a Bare Engine Block
A = Is for the Design Changes in this case its for a First Year Part.
So there can be a problem after this many years and in many case multiple rebuilds of these Engines the 240 & 300 share the exact same Block dimensions. So you could Swap have a 240 Rotating Assembly in a 240 block or a also 300 Rotating Assembly into a 240 block creating a Hybrid combo, so measuring the stroke or else by checking the internal Cast Part Numbers on the Connecting Rods and Crankshaft is the only sure way to tell what you have.
Q: Some guy gave me a free 300, and I want to rebuild it and put it in my Bronco. But I want to be sure I order the right parts, how do I figure out what year the motor is?
A: Start by finding the Block and Heads Design / Casting Numbers they can get you real close to the year. Example C8TE-6015-A
the first four will tell you what the First year the Part was Designed by Ford
C = 1960
8 = Is the year added to above gives you 1968
T = The Ford Parts Division that ordered the part to be made T = Ford Truck Division
E = Is who Made the Part E = The Ford Engine Foundry
The next Number is the Generic Part Id
6015 = A Bare Engine Block
and Last is the number of Revisions that the Part has went through
A = the First Design of the Part.
For the Original 300 Engine Blocks all this info is going to remain the same except for the first two, I.E. the Letter and the Number
they can range from
C5 to up to maybe F6 I have not yet verified the real late model blocks and heads numbers made for the 1995 to 1997 year models Generally though. C = 1960, D = 1970, E = 1980, F = 1990, then you just add in the number after the first letter for the basic part year. The last Letter or Letters can also change depending on how many times the part was improved or changed from the Original Part.
Next we can really fine tune this above info just by finding the Block or Heads Casting Date Code. These will look like a small Metal Plate with a straight Blade Screw Head on each end. They can have 2 to 3 Numbers and 1 Letter, Note that these Part Designs can be continued over for more than one year. Adding to the above example of C8TE-6015-A we find there is also a Casting Date Code of 9W8 using the Chart below this is found to be a second year part and decodes as Sept. 08, 1969
Q: What's a 300 weigh?
A: About 560 lbs. with both the Intake & Exhaust Manifolds plus the Flywheel.
Q: I've heard a lot about using Chevy inline six rocker arms for a cheap performance gain, what is this? How hard is it to do?
A: I think FTF should get credit for this up grade he was one of the very First if not the First that I ever heard of doing it, there have now been many that have now done this swap.
The stock Ford Six Rocker Arms have a 1.6 Ratio. The Higher Ratio (1.75) Chevy 230 ci, 250 ci, & 292 ci, Inline Six Rocker Arm Swap gives you more Valve Lift and a little more Cam Duration, its a proven increase in power for a 240 or 300 Ford Six for a quick bolt on Mod. These Rocker Arms and Fulcrums are available at most of your local Auto Parts Stores or online, there is also a Comp Cams Rocker Arm Kit & maybe a Crane Cams kit still too. The early model Carb Heads have a Broached Slot to guide the Push Rods most will convert the stock Ford pressed in studs over to the Screw In Studs, but it really depends on how much Valve Spring Pressure you are going to run, the SBC, BBC or SBF screw in Studs are used for this conversion. On the later heads that have a round hole then you will also need to use Push Rods Guide Plates to keep the Rocker Arms in their proper alignment. The Guide Plates to use are the slotted type so they can be Tack Welded in the correct position pmuller9 figured out an assembly to align them to set them up quickly there are some variations on some of the heads that may cause some to differ.
Comp Cams 230, 250, & 292 Chevy Rocker Arm set of 12
www.summitracing.com
Melling 230, 250, & 292 Chevy Rocker Arms one per about the lowest cost version.
www.summitracing.com
Additional Notes
Site member "pmuller9" said "Get the SBC V8 rocker arm pivot balls that fit a 3/8" stud.
Your local auto parts stores should carry them.
The ones pictured here have grooves for better oiling.
https://www.summitracing.com/parts/cca- ... /chevrolet.
Just a side note:
The lifter spacing is more than the valve stem spacing so the pushrods come up at an angle.
The center to center spacing at the valves and rocker studs are close to 1.90"
The pushrod spacing is about 1.94" at the pushrod guides.
When you tighten the rocker studs you may want to angle the pushrod guides out just a little so the rocker arm tips are centered on the valve stems. Not a big deal but every little fine tuning helps"
Q: Thinking about Roller Rockers?
A: Their is one direct bolt on option for the 1987 to 1997 Ford 4.9 EFI engines, the Scorpion pedestal mount roller rocker with a 1.73 ratio.
https://www.summitracing.com/parts/scc- ... /make/ford
For the Ford 240 / 300 Carb Heads it is possible to use the BBC 1.75 Roller Rocker Arms if you set them up right.
There are also the 1.6 Harland Sharp Roller Rocker Arms that are made for the Ford Six they work excellent and fit all the Carb heads with the Stud mounted Rocker Arms. It is also popular to install the Screw in Rocker Studs to replace the Pressed in Studs.
Rocker Arm Mounting Stud Sizes.
3/8 inch Stud. https://www.summitracing.com/parts/csp-s4002/make/ford
7/16 inch Stud. https://www.summitracing.com/parts/csp-s4002-7/make/ford
Chevy 230, 250, and 292 Type Roller Rocker Arms should also be able to work too since the stock Rockers Arms Fit.
Harland Sharp 3/8 inch stud. https://www.summitracing.com/parts/csp-s3002/make/chevrolet
Harland Sharp 7/16 inch stud. https://www.summitracing.com/parts/csp-s3002-7/make/chevrolet
Crower has some really good looking Enduro Roller Rocker Arms in Stainless Steel too.
3/8 Inch Stud. https://www.summitracing.com/parts/cro-73631-12/make/chevrolet
7/16 Inch Stud. https://www.summitracing.com/parts/cro-73629-12/make/chevrolet
Q: I was wondering if the Non-EFI head will work with the EFI intakes?
A: http://fordsix.com/forum/viewtopic.php?t=48366
Q: Common Cam profiles, including stock:
A: http://fordsix.com/forum/viewtopic.php?t=48357
Q: I think I have a forged steel crank in my 300. How do I tell?
A: http://fordsix.com/forum/viewtopic.php?t=46878
Q: Do I have any options for a crossflow head besides the one in development by Classinc Inlines?
A: http://fordsix.com/forum/viewtopic.php?t=48372
Q: Motor Mount Coordinates
http://fordsix.com/forum/viewtopic.php?p=365107
Q: Has anyone ever put the larger valves into a newer EFI head?? I have read somewhere that there is a clearance issue when installing the Larger Chebby valves into the EFI head?
A: http://fordsix.com/forum/viewtopic.php?t=48369
Q: Anyone know the CFM ratings of the various Motor Craft 2100 & 2150 carbs?
A: http://fordsix.com/forum/viewtopic.php?p=365109
Q: Anyone with a 53-64 F100 that is considering swapping in a Ford 240/300 inline 6 cylinder?
A: http://fordsix.com/forum/viewtopic.php?t=46462
Q: how can I tell the difference between a 240 and a 300?
A: If the Head is off the best way is to measure the Stroke Length a 240 has a Stroke of "3.18".
The 300 Six has a stroke "3.98"
Or you could also put a stiff wire or long Screw driver down the #1 Spark Plug Hole at TDC make a mark there on your wire or screw driver and then turn crank to BTDC make another mark now measure the distance from the two marks and compare to the above measurements to get your Stroke Length.
Another way is to look at the Design Casting Numbers on the Block and the Head. Original Engines would be decoded like this
A 240 engine would have these Prefix Number and Letters I believe that Fords first use for the 240 Six was in the Big Ford Cars their first year of this Design Code is C5AE-6015-A
C = 1960
5 = Is the year added to the above gives you 1965
A = The Ford division that ordered that Part be made is, A = The big Ford Car Model Line
E = The Division that made the Part = Ford Engine Foundry
6015 = Ford's Generic Part Number for a Bare Engine Block it will be the same for any Ford Engine Block
A = Is for the Design Changes in this case its for a First Year Part.
These 240 engines were also used in the 1965 Ford Pick Ups but they will still have that AE in their Design numbers on their blocks and Heads.
The 300 Six also came out in 1965 but it was designed for use in the Ford Pick Up's and Ford never officially installed them in the Big Ford Cars for sale to the public.
C = 1960
5 = 1965
T = The Ford Truck Division
E = The Ford Engine Foundry
6015 = Ford's Generic Part Number for a Bare Engine Block
A = Is for the Design Changes in this case its for a First Year Part.
So there can be a problem after this many years and in many case multiple rebuilds of these Engines the 240 & 300 share the exact same Block dimensions. So you could Swap have a 240 Rotating Assembly in a 240 block or a also 300 Rotating Assembly into a 240 block creating a Hybrid combo, so measuring the stroke or else by checking the internal Cast Part Numbers on the Connecting Rods and Crankshaft is the only sure way to tell what you have.
Q: Some guy gave me a free 300, and I want to rebuild it and put it in my Bronco. But I want to be sure I order the right parts, how do I figure out what year the motor is?
A: Start by finding the Block and Heads Design / Casting Numbers they can get you real close to the year. Example C8TE-6015-A
the first four will tell you what the First year the Part was Designed by Ford
C = 1960
8 = Is the year added to above gives you 1968
T = The Ford Parts Division that ordered the part to be made T = Ford Truck Division
E = Is who Made the Part E = The Ford Engine Foundry
The next Number is the Generic Part Id
6015 = A Bare Engine Block
and Last is the number of Revisions that the Part has went through
A = the First Design of the Part.
For the Original 300 Engine Blocks all this info is going to remain the same except for the first two, I.E. the Letter and the Number
they can range from
C5 to up to maybe F6 I have not yet verified the real late model blocks and heads numbers made for the 1995 to 1997 year models Generally though. C = 1960, D = 1970, E = 1980, F = 1990, then you just add in the number after the first letter for the basic part year. The last Letter or Letters can also change depending on how many times the part was improved or changed from the Original Part.
Next we can really fine tune this above info just by finding the Block or Heads Casting Date Code. These will look like a small Metal Plate with a straight Blade Screw Head on each end. They can have 2 to 3 Numbers and 1 Letter, Note that these Part Designs can be continued over for more than one year. Adding to the above example of C8TE-6015-A we find there is also a Casting Date Code of 9W8 using the Chart below this is found to be a second year part and decodes as Sept. 08, 1969
This is what a Casting Date Code looks like they can be located in different locations on the many different Ford engine blocks but they will still look like and will be in this basic format. 
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Q: What's a 300 weigh?
A: About 560 lbs. with both the Intake & Exhaust Manifolds plus the Flywheel.
Q: I've heard a lot about using Chevy inline six rocker arms for a cheap performance gain, what is this? How hard is it to do?
A: I think FTF should get credit for this up grade he was one of the very First if not the First that I ever heard of doing it, there have now been many that have now done this swap.
The stock Ford Six Rocker Arms have a 1.6 Ratio. The Higher Ratio (1.75) Chevy 230 ci, 250 ci, & 292 ci, Inline Six Rocker Arm Swap gives you more Valve Lift and a little more Cam Duration, its a proven increase in power for a 240 or 300 Ford Six for a quick bolt on Mod. These Rocker Arms and Fulcrums are available at most of your local Auto Parts Stores or online, there is also a Comp Cams Rocker Arm Kit & maybe a Crane Cams kit still too. The early model Carb Heads have a Broached Slot to guide the Push Rods most will convert the stock Ford pressed in studs over to the Screw In Studs, but it really depends on how much Valve Spring Pressure you are going to run, the SBC, BBC or SBF screw in Studs are used for this conversion. On the later heads that have a round hole then you will also need to use Push Rods Guide Plates to keep the Rocker Arms in their proper alignment. The Guide Plates to use are the slotted type so they can be Tack Welded in the correct position pmuller9 figured out an assembly to align them to set them up quickly there are some variations on some of the heads that may cause some to differ.
Comp Cams 230, 250, & 292 Chevy Rocker Arm set of 12
CHEVROLET COMP Cams 1261-12 COMP Cams High Energy Rocker Arms | Summit Racing
Free Shipping - COMP Cams High Energy Rocker Arms with qualifying orders of $109. Shop Rocker Arms at Summit Racing.
Melling 230, 250, & 292 Chevy Rocker Arms one per about the lowest cost version.
CHEVROLET Melling MR-844 Melling Rocker Arms | Summit Racing
Free Shipping - Melling Rocker Arms with qualifying orders of $109. Shop Rocker Arms at Summit Racing.
Additional Notes
Site member "pmuller9" said "Get the SBC V8 rocker arm pivot balls that fit a 3/8" stud.
Your local auto parts stores should carry them.
The ones pictured here have grooves for better oiling.
https://www.summitracing.com/parts/cca- ... /chevrolet.
Just a side note:
The lifter spacing is more than the valve stem spacing so the pushrods come up at an angle.
The center to center spacing at the valves and rocker studs are close to 1.90"
The pushrod spacing is about 1.94" at the pushrod guides.
When you tighten the rocker studs you may want to angle the pushrod guides out just a little so the rocker arm tips are centered on the valve stems. Not a big deal but every little fine tuning helps"
Q: Thinking about Roller Rockers?
A: Their is one direct bolt on option for the 1987 to 1997 Ford 4.9 EFI engines, the Scorpion pedestal mount roller rocker with a 1.73 ratio.
https://www.summitracing.com/parts/scc- ... /make/ford
For the Ford 240 / 300 Carb Heads it is possible to use the BBC 1.75 Roller Rocker Arms if you set them up right.
There are also the 1.6 Harland Sharp Roller Rocker Arms that are made for the Ford Six they work excellent and fit all the Carb heads with the Stud mounted Rocker Arms. It is also popular to install the Screw in Rocker Studs to replace the Pressed in Studs.
Rocker Arm Mounting Stud Sizes.
3/8 inch Stud. https://www.summitracing.com/parts/csp-s4002/make/ford
7/16 inch Stud. https://www.summitracing.com/parts/csp-s4002-7/make/ford
Chevy 230, 250, and 292 Type Roller Rocker Arms should also be able to work too since the stock Rockers Arms Fit.
Harland Sharp 3/8 inch stud. https://www.summitracing.com/parts/csp-s3002/make/chevrolet
Harland Sharp 7/16 inch stud. https://www.summitracing.com/parts/csp-s3002-7/make/chevrolet
Crower has some really good looking Enduro Roller Rocker Arms in Stainless Steel too.
3/8 Inch Stud. https://www.summitracing.com/parts/cro-73631-12/make/chevrolet
7/16 Inch Stud. https://www.summitracing.com/parts/cro-73629-12/make/chevrolet
Q: I was wondering if the Non-EFI head will work with the EFI intakes?
A: http://fordsix.com/forum/viewtopic.php?t=48366
Q: Common Cam profiles, including stock:
A: http://fordsix.com/forum/viewtopic.php?t=48357
Q: I think I have a forged steel crank in my 300. How do I tell?
A: http://fordsix.com/forum/viewtopic.php?t=46878
Q: Do I have any options for a crossflow head besides the one in development by Classinc Inlines?
A: http://fordsix.com/forum/viewtopic.php?t=48372
Q: Motor Mount Coordinates
http://fordsix.com/forum/viewtopic.php?p=365107
Q: Has anyone ever put the larger valves into a newer EFI head?? I have read somewhere that there is a clearance issue when installing the Larger Chebby valves into the EFI head?
A: http://fordsix.com/forum/viewtopic.php?t=48369
Q: Anyone know the CFM ratings of the various Motor Craft 2100 & 2150 carbs?
A: http://fordsix.com/forum/viewtopic.php?p=365109
Q: Anyone with a 53-64 F100 that is considering swapping in a Ford 240/300 inline 6 cylinder?
A: http://fordsix.com/forum/viewtopic.php?t=46462
Last edited by a moderator:
