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I'm looking at buying a 1967 galaxie 500. The emblem on the car says it's a 390 motor, but the owner told me that some one put a 428 in it. I know there is probably not a lot of difference between the two motors, but does anyone know of a way to tell if it really is a 428 and not a 390. Any comments are very appreciated.
 

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You could check the casting number, but that may not be enough. Some casting numbers overlapped different engines.

The more valuable component might be the heads and intake anyway. Can you get a casting number off the heads and intake?
 

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I could Possibly get the numbers off the heads, but it might be dificult since I don't own the car. The intake is after market, So I don't think that it would offer any usefull information. Any other Ideas?
 

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If you and/or the owner believes that having the 428 motor adds significant value to the car. I would leave it up to the owner to provide the proof. If it can't be proven, I would assume the worst case scenario and make the purchase accordingly.

If the owner can't prove it or provide you with enough information to verify it yourself, you are going to be left with the same burden if you ever try to sell it.

Is this supposed to be a "special" 428, like a PI or Cobra Jet? If not, it probabaly doesn't matter that much and the only way to "truly" verify it is to pull out the spark plugs and measure the stroke.
 

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Hello.:) The differences between the two are internal. It's the spinning assembly inside, as in bore diameter, stroke, etc.. If that 428 left the factory in a car, it will have the cars vin on the back of the d/s cylinder head, or possibly the front of the p/s, if someone switched them around during a rebuild. Barring that possibilty, you would just about have to either snatch one head off and measure the cylinder bore, pull the oil pan and check the rods, crank, etc... or take the guys word for it. I really don't see that affecting the value of the vehicle, though, whichever one it has. :)
 

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Another thing to check is the damper for a counterweight. 428's were externally balanced and other FE's were internal.
 

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428/390 difference.

JGard was right, another way is to check the front damper. I am no expert but as I understand it the front damper on a 67 GT390 has the pulley built into/onto the damper where as my 428 has bolt on front pulleys. Pulley.JPG
 

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Supposedly a 428 in 1970 F250

I'm buying a truck from a friend (2nd owner) that originally had a 390 2bbl, per the Marti report. However, the original owner's son, who sold it to my friend, said his dad installed a 428 out of a '69 T-bird, as he pulled his drag boat with the truck. My research says it couldn't be from a 69 bird, as they all had 429s. The truck's been stored in a garage since 2004, and the engine paint still looks good, so I don't think it was in there for very long before he died. My concern is that I buy the correct parts for the engine, thankfully parts like plugs, oil filter, etc I can remove and match up before purchasing. But it would be nice if I knew for sure it was a 428FE. Other than the pulley being part of or bolted to, is there anything else visible on the outside of the engine? It has an aluminum Edelbrock intake and Edelbrock 600 4bbl which I don't plan on removing. As for measuring the stroke, what tool would I use to do that?
Mark, Victorville, CA
1970 F250 Sport Custom Camper Special, 428 (I think), C6
1977 IH Scout II, 345, 727 auto
1942 Farmall B w/exhaust lift and B-238 cultivator
2013 Honda Accord EX V-6 (the wife's)
 

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Another thing to check is the damper for a counterweight. 428's were externally balanced and other FE's were internal.
ONLY the SCJ has a counterweight on the dampner spacer. Regular and CJ 428's are neutral balanced in front and counter weighted on the flywheel only.
Randy
 

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An easy way on an auto trans application is to look at the flex plate. A 390 is smooth and a 428 has triangular cutouts + the above mentioned counter weight. A stick flywheel has a visible counter weight cast into it too.
Randy
 
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