Boss 300
Fleet Mechanic
Joined: Nov 2002
Posts: 1,643
Likes: 69
The bore spacing for a 300 six is 4.480"
The bore spacing for a Cleveland and Boss V8 is 4.380".
The only way a Cleveland head will match up to a 300 six is to machine six separate chambers and space them at 4.480" accordingly.
Often times the head bolts are increased from 7/16" to 1/2" for increased clamping force on the head gasket.
The bore spacing for a Cleveland and Boss V8 is 4.380".
The only way a Cleveland head will match up to a 300 six is to machine six separate chambers and space them at 4.480" accordingly.
Often times the head bolts are increased from 7/16" to 1/2" for increased clamping force on the head gasket.
4wd Low
Joined: Sep 2020
Posts: 14
Likes: 5
Thanks for the explanation. Coming from small turbocharged engines I'm familiar with porting heads and minor mechanical work, so much with those motors is about the computer tuning. I am constantly impressed with the ingenuity of the earlier generation of hot rodders and racers when there was no such thing as a "bolt-on" modification, everything seems to involve the vertical mill and the welding rig and some actual engineering know how. I love this kind of stuff where some smart guys basically re-engineer a motor using parts from every manufacturer!
Super Moderator
Joined: Apr 2004
Posts: 34,495
Likes: 2,809
I thought they did 3 sections on the "close enough" principle.
Most of the links I found are gone. There are some pics.
But there is also an alternative:
https://engineswapdepot.com/?p=4014
Most of the links I found are gone. There are some pics.
But there is also an alternative:
https://engineswapdepot.com/?p=4014
Moderator
Joined: Dec 2007
Posts: 7,987
Likes: 104
From: Boise, Idaho
I thought they did 3 sections on the "close enough" principle.
Most of the links I found are gone. There are some pics.
But there is also an alternative:
https://engineswapdepot.com/?p=4014
Most of the links I found are gone. There are some pics.
But there is also an alternative:
https://engineswapdepot.com/?p=4014
The #2 and #5 cylinders were centered, and then their left and right companions were just a hair off.
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TheDudeAbides
Ford Inline Six, 200, 250, 4.9L / 300
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Jul 29, 2022 01:26 PM
