Factory Overdrive??
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
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From: Simi Valley, CA
But I doubt that it's sitting on a 300 short block. 
What's the casting number on the "300" block?
Lead Driver
Joined: Mar 2008
Posts: 7,182
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From: Near Los Angeles
The 240 and 300 use the same block. The 300 is a stroked 240. Also, it is a common practice to put a 240 head on a 300. Since the 240 has smaller c.chamber (68cc) compared to the non efi 300 head (76cc). Changing to the 240 head on a 300 bumps the compression ratio for a bit more power. So yes, that 240 head you mentioned could well have been on a 300. The only way to tell one from the other is to measure the stroke. Iirc, the 240 has a stroke down around 3.18", whereas the 300 has a 3.98" stroke.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 785
From: Simi Valley, CA
The 240 and 300 use the same block. The 300 is a stroked 240. Also, it is a common practice to put a 240 head on a 300. Since the 240 has smaller c.chamber (68cc) compared to the non efi 300 head (76cc). Changing to the 240 head on a 300 bumps the compression ratio for a bit more power. So yes, that 240 head you mentioned could well have been on a 300. The only way to tell one from the other is to measure the stroke. Iirc, the 240 has a stroke down around 3.18", whereas the 300 has a 3.98" stroke.
Logistics Pro
Joined: Jul 2005
Posts: 4,217
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I think the story behind my truck is that they had a door and frame with matching VINs, and a big ol' pile of miscellaneous parts - that and some code S Bright Dark Blue Metallic and a sprayer...
Fleet Mechanic
Joined: Nov 2009
Posts: 1,398
Likes: 6
I had an 83 SC Bullnose 351W and a granny 3sp w/OD. The shops around here called it a four speed. That got me about 17mpg all around. I also had an 84 Bullnose 300 inline and a 3sp w/OD that the shops also called it a 4 speed. That one only got me 12mpg.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 785
From: Simi Valley, CA
8J6 is the head casting date code. Cast September (J) 6, 1968 (8).
240/300: The block and the head are the same. 240 cancelled at the end of the 1974 model run.
Logistics Pro
Joined: Jul 2005
Posts: 4,217
Likes: 154
C6AE-6015-D is the block casting number, reflects 1966. Casting numbers are foundry marks, cannot be cross referenced to Ford part numbers.
8J6 is the head casting date code. Cast September (J) 6, 1968 (8).
240/300: The block and the head are the same. 240 cancelled at the end of the 1974 model run.
8J6 is the head casting date code. Cast September (J) 6, 1968 (8).
240/300: The block and the head are the same. 240 cancelled at the end of the 1974 model run.
One of these days I've got to pull a plug and try to get a rudimentary measurement of the stroke, because I've been curious about this...
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