Ford 390 V8 engine swap

[Bob Shafto]

So I’d like to replace my existing (tired) Galaxie 500 390 V8 with a long block motor, available from several sources. I’m guessing the trick is to get the right version of this motor since variations in bolt holes, motor mounts, etc. may vary between full size cars, Mustangs, Mercuries, Cougars, Thunderbirds, etc.

 

The engine block number should be the key. I’ve learned that 390 motors, offered from 1961 to 1973, should have block numbers starting with the letter C followed by a single digit (6 in my case). C denotes the 1960s decade, and 6 the specific year (1966). What I can’t find a clear explanation for is what the next letter(s) should be (I can’t see the block number on my motor because it is hidden by the exhaust manifold and pipes). The shop manual offers no help here, but does say that the 390 motor “model prefix” should have an ESS designation (location no specified).

 

One website states that full sized cars would have the letter A following the “6”; trucks a “T”; Thunderbirds “S” and, by inference, other models with other letters. The fourth digit (letter) is usually an E (for Engine). So that sounds reasonable enough: Ideally, I need to find a motor with an engine number that starts with C6AE.

 

What I don’t have a clue about is whether motors from other years likely swap in easily or should I only get one that was made for 1966 models (or maybe 65 & 67 as well)?

 

Any advice would be much appreciated!

[misterc9]

 You know what year and model your car is. A Hollander interchange manual can tell you what other Year and model engines will fit.  It also has a lot of information on the numbers.

[m-mman]

What your are referring to are part numbers C6AZ. . .  B7AA. . . D1AZ. . . They made subtle changes over the years BUT it can be confusing because the part number states where the part was FIRST USED and not an interchangeability. (example The FE 4 bbl manifold typically has a Thunderbird prefix because the 4 bbl version was first made for it and then "borrowed" for the Galaxie. (All Galaxies would have a "T-bird" manifold) 

 

But if you are looking for an engine to swap and are not interested in numbers matching or show cars then know that FoMoCo went from motor mounts with 2 bolts to mounts with 3 bolts in 1965.

If you have a 1966 car then ask for a 65 or newer block.

 

The heads all interchange. (there are differences in valves and combustion chambers that are of interest to performance builders). In 66 to 68 they had holes for the air injector system but these can be plugged if needed. 

[JamesR]

When I bought my '65 T-Bird, I discovered it had a 390 out of a '67 Mercury...or so I thought. There are some very knowledgeable folks over the fordbarn.com. They've been through this stuff a lot. Apparently the casting numbers on the block are a pretty good guide, but not exactly the Ten Commandments of Ford motor ID, at least according to some fordbarn folks and as m-mman suggests.  I don't have an original T-Bird motor, but beyond that I don't get real specific.  Late '60's Merc or Ford...most likely Merc.

 

I had to read my casting number upside down with a mirror lying on my back. That was the only way I could see it. One thing you should keep in mind if you're buying an old engine from someone: it's difficult to tell an FE 390 from a FE 360, (and I think a 352 if you go into the 1960's early enough.) One of the more reliable ways to  tell the difference is to remove spark plugs and measure the stroke. That's what I did when deciphering my T-Bird engine. As I recall, the 360 and 352 have something like a 3.5" stroke and the 390 has about a 3.7" stroke. Going off of memory, so verify. Good luck.

Edited June 8, 2021 by JamesR (see edit history)

[Bob Shafto]

Great advice guys, thanks so much.

 

 

[Bob Shafto]

Just visited my local salvage yard and learned from their Hollander's Manual that 1966 to 1970 390 motors interchange. Should be all set now. Thanks again.

 

 

[1912Staver]

There is a difference effecting head interchange. The head drillings for the exhaust manifolds on Galaxy's , Thunderbirds and Pickup's have a vertical orientation. The drillings for Mustangs, Torino's, Fairlane's, Cougars Etc.  have as staggered horizontal orientation. Later head castings have the extra material needed for the horizontal holes even if the heads have the vertical pattern drilled and tapped from the factory. So they can be converted to the horizontal style if needed. But early heads are vertical pattern only, they lack the material needed for one of the bolts at each exhaust port.

[jrbartlett]

Why not have a good rebuilder go through your existing engine? Then you'd know exactly what was done, or could customize to your preferences. 

[Paul Dobbin]

12 hours ago, JamesR said:

When I bought my '65 T-Bird, I discovered it had a 390 out of a '67 Mercury...or so I thought. There are some very knowledgeable folks over the fordbarn.com. They've been through this stuff a lot. Apparently the casting numbers on the block are a pretty good guide, but not exactly the Ten Commandments of Ford motor ID, at least according to some fordbarn folks and as m-mman suggests.  I don't have an original T-Bird motor, but beyond that I don't get real specific.  Late '60's Merc or Ford...most likely Merc.

 

I had to read my casting number upside down with a mirror lying on my back. That was the only way I could see it. One thing you should keep in mind if you're buying an old engine from someone: it's difficult to tell an FE 390 from a FE 360, (and I think a 352 if you go into the 1960's early enough.) One of the more reliable ways to  tell the difference is to remove spark plugs and measure the stroke. That's what I did when deciphering my T-Bird engine. As I recall, the 360 and 352 have something like a 3.5" stroke and the 390 has about a 3.7" stroke. Going off of memory, so verify. Good luck.

  I had a 390 in my 57 Ranchero with a two bolt motor mount.    I heard the 390 was actually the 352 bored out to 390 by

  FOMCO.

  Interchangeabiity can be tricky on Fords.  The book said I could use 302 heads on a 289 Mustang.  When the engine  was     

  rebuilt,  the heads  had to be drilled and tapped for the A/C brackets.  Just more Ford fun!

Edited June 8, 2021 by Paul Dobbin
reposition text (see edit history)

[junkyardjeff]

From what I have read you can put the 65 and newer FE in a 64 and older but can not put the 64 and older FEs in a 65 and newer due to the moto mount holes in the block.