351m/400m
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Freshman User
Joined: Jan 2003
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351m/400m
Hey-I need some help. I am going to be putting a new 400M in my 79 f-150 and am considering several performance upgrades. After some reaserch I have found that the 400 is based on the 351C. Some of the parts are 100% interchangeable including the cylinder heads. I know that the deck heights on the two engines are different so the intake manifolds are not interchangeable. I want to use a set of 1971 4V heads from the 351C on my 400 for two reasons: The bigger port sizes and because of the 62.6cc combustion chamber on the heads wich compared to the 76cc heads of the 400 would make a 9.5:1 compression ratio on the 400.
My question is is this a good idea-there's got to be somebody who has tried this before, right?
There are adapters that you can buy to put the stock 351C 4V manifold on the 400/351C head combo but I'm wondering if I can use my Edlbrock performer 400 manifold on the combo because of the bigger ports on the 351C heads. Any help would be greatly appretiated-Thanks
My question is is this a good idea-there's got to be somebody who has tried this before, right? There are adapters that you can buy to put the stock 351C 4V manifold on the 400/351C head combo but I'm wondering if I can use my Edlbrock performer 400 manifold on the combo because of the bigger ports on the 351C heads. Any help would be greatly appretiated-Thanks 
Elder User
Joined: Feb 2001
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From: Porterfield
351m/400m
Yes there a few of us out here that have done this swap.
But if you going to be using this as your daily driver or rock crawler or off roading truck, I'd stay with the 2V style head. And if you need the 65.0 cc chambers then I'd opted out for the Aussie 302c 2V heads..
The problem you run into with the 4V heads is the ports are so big you lose the port volicity and unless your spinning 4500 RPM's or more they really suck.
Also on all my 4V heads I use the intake port stuffer to help out on the bottom end.
But if you chose to go this route anyway here's some number of a place to get the intake plates and port stuffers.
Price Motorsports Eng.
812-546-4220
Mary can fix you up with everything you need to make this happen.
And I use the Torker 351c 4v Intake. Which I have an Brand New Extra one sitting on my shelve.
ShaZam
But if you going to be using this as your daily driver or rock crawler or off roading truck, I'd stay with the 2V style head. And if you need the 65.0 cc chambers then I'd opted out for the Aussie 302c 2V heads..
The problem you run into with the 4V heads is the ports are so big you lose the port volicity and unless your spinning 4500 RPM's or more they really suck.
Also on all my 4V heads I use the intake port stuffer to help out on the bottom end.
But if you chose to go this route anyway here's some number of a place to get the intake plates and port stuffers.
Price Motorsports Eng.
812-546-4220
Mary can fix you up with everything you need to make this happen.
And I use the Torker 351c 4v Intake. Which I have an Brand New Extra one sitting on my shelve.
ShaZam
