Yea, but nothing's as sexy as a huge 8-71 huffer pokin up outa the hood with twin Holleys 
391 performance options
Fleet Mechanic
Joined: Jul 2000
Posts: 1,491
Likes: 343
From: SE Iowa
Originally Posted by baddad457
Supercharge It!!!!!!!!!!!!!!
http://cgi.ebay.com/ebaymotors/Ford-...QQcmdZViewItem
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Junior User
Joined: Mar 2007
Posts: 81
Likes: 0
The truck i am planning on putting it in is an 85 f-250 farm truck that has a straight six in it. The six in it is running on like five and a half cylinders right now and is getting worn out. I helped a cousin of my remove the 390 or 391 from an f-700 and he said I coud have it for 50 bucks and I heard it run before hand and it sounded great. How do you figure out the compression ratio from looking at the pistons and the head volume? If this thing did get swapped with fe parts since there are signs that it was taken apart before, i would be happy if it got 8.6:1. Even so, I mainly want to put a bigger cam etc. on this engine for fuel economy and also a little more oomph for pulling wagons with it since it is a farm truck and all.
Elder User
Joined: Mar 2004
Posts: 747
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From: Klamath Falls OR
Well, Bring the #1 piston up to TDC. You can CC (use the spark plug hole)and see how much volume you have. I have a Moroso Power speed calculator. And I can tell ya your compression ratio! How does that sound
Elder User
Joined: Mar 2004
Posts: 747
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From: Klamath Falls OR
You measured the cc with a beaker! You can buy one from summit racing. And the 391 has a Larger snout then any FE. Sounds like you may need to buy a book. Good stuff in the book and great for a reference as well. You should Google Ford 391 and see what you come up with! JMO
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Junior User
Joined: Jun 2005
Posts: 64
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From: Friendswood, Texas
391 Snout
Here is my 391 crank.
Look at the size of the snout, there were 2 different sizes but both are larger than an FE snout.
http://s153.photobucket.com/albums/s...t=IMG_5516.jpg
Richard.
Look at the size of the snout, there were 2 different sizes but both are larger than an FE snout.
http://s153.photobucket.com/albums/s...t=IMG_5516.jpg
Richard.
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Junior User
Joined: Mar 2007
Posts: 81
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Is the inside diameter of the gear bigger but the timing gears are the same size as regular FEs or is the inside diameter bigger and also the timing gears are bigger? Could it be possible to mill out a regular fe gear and make it fit onto my 391 snout?
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Junior User
Joined: Mar 2007
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Well I got the heads off. The valve sizes are standard 2.02"/1.5". I have a 73 to 79 ford truck repair manual, which doesn't cover 361/391 engines. My pistons have valve reliefs that are identical to ones in a photo in the book showing 360 and 390 pistons. They look like this
()
() .
Which brings another question up: If 360/390 have the same style pistons as my 391 has and they are rated at 8.6:1 compression, how could this make these engine have lower compression? I am pretty sure it is an FT because my distributor gear on my camshaft is bigger than a standard 390 gear. It also has a 1/4" oil pump shaft and has the cast iron timing cover, front mount, and a sumpless oil pan. I know I keep writing a lot but I'm searching for answers from some very reliable sources. I am only 18 and need to learn a lot yet, so I hope you guys don't mind that I'm picking your brains too much. Thanks a lot though. I greatly appreciate it.
()
() .
Which brings another question up: If 360/390 have the same style pistons as my 391 has and they are rated at 8.6:1 compression, how could this make these engine have lower compression? I am pretty sure it is an FT because my distributor gear on my camshaft is bigger than a standard 390 gear. It also has a 1/4" oil pump shaft and has the cast iron timing cover, front mount, and a sumpless oil pan. I know I keep writing a lot but I'm searching for answers from some very reliable sources. I am only 18 and need to learn a lot yet, so I hope you guys don't mind that I'm picking your brains too much. Thanks a lot though. I greatly appreciate it.
Last edited by ford390fe; Jul 5, 2007 at 04:03 PM.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 783
From: Simi Valley, CA
FT
C8TZ-6256-A .. Cam Sprocket - Iron - 48 Teeth
C4TZ-6268-A .. Timing Chain - 64 Links
C4TZ-6306-A .. Crank Sprocket (361/391)
-----------------------------------
FE
C8AZ-6256-A .. Cam Sprocket - 36 Teeth
D0AZ-6268-A .. Timing Chain - 48 Links
C4AZ-6306-A .. Crank Sprocket - 18 Teeth
C8TZ-6256-A .. Cam Sprocket - Iron - 48 Teeth
C4TZ-6268-A .. Timing Chain - 64 Links
C4TZ-6306-A .. Crank Sprocket (361/391)
-----------------------------------
FE
C8AZ-6256-A .. Cam Sprocket - 36 Teeth
D0AZ-6268-A .. Timing Chain - 48 Links
C4AZ-6306-A .. Crank Sprocket - 18 Teeth