There are some Ford engines that look exactly alike, so determining C.I.D. in a salvage yard, or with an engine still in the car can be a chore sometimes. Certain displacement FE engines, late 60's 289-302's, 351M-400's and 429-460's are virtually impossible to tell apart from each other. Here is a quick and easy method to determine the stroke of the crankshaft that will either hint at, or tell you for certain what C.I.D. engine you are looking at.

Case in point was an FE that a buddy of mine bought. It came out of a '66 Thunderbird that the owner swore was a 428. The engine had all the original pieces in place, it was a four barrel engine, the air filter housing had a 428 decal on it, and the block had the C6ME-A casting number on it, which all books told us was a 428. I was still a bit skeptical. I was going to measure the stroke to see for myself.






The first step was to get the number one cylinder to top dead center by aligning the zero mark on the balancer with the timing mark on the engine.






A way to measure was going to be needed. I use a piece of brake line tubing, and a small scribe.






After removing the number one spark plug, the piece of tubing is inserted into the spark plug hole and is held perpendicular.






The scribe is then used to make a mark on the tubing at the height of the valve cover rail. The valve cover rail is used as a commom reference point.






Since the number one piston is at the very top of the cylinder, the number four piston will be at the very bottom of the cylinder. After inserting the same piece of tubing into the number four spark plug hole, another mark is made that corresponds with the valve cover rail.










We are now left with two marks on the tubing.






Measuring between the two marks will tell you the stroke of the crankshaft. The measurement I got was 3 1/2", which was not the 3.98" I was looking for if the engine was a 428. I was looking at a 352 or 360 C.I.D. engine.






This procedure can be used on any engine to figure out the stroke, which will give you a better idea of what you are looking at.

Here are the crankshaft strokes of a few Ford engines:


-289- 2.87"
-302-3.00"
-352 FE-3.50"
-390 FE-3.78"
-428 FE-3.98"
-351M-3.50"
-400-4.00"
-429-3.59"
-460-3.85"



I also used this method to I.D. a Y-block Ford that I recently purchased. The seller swore up and down that it was a 292, but a little measuring told that it was a 312 because of the 3.44" stroke that I measured. This method could also be used on any engine that you need to I.D. in the car or wherever it is.

 

Excellent information! This should help a lot of people out. Thank you.

 

brilliant idea, I never thought that you could measure it with a 'stick' that you had to have something that could bend. what i'm saying is that the spark plug hole is not right on top of the cylinder but offset, so if you place it in such a way that it hits piston and wall at the far spot of hole and do the same thing on #4 the angle is off, readings are off ?!

 

Good job on the stroke. I hope you're not planing to use those heads in a Mustang, though.

 

The spark plus holes are big enough to allow the "stick" to enter straight up and down. Even if you were slighly off from perpendicular, as long as the angle was the same for both cylinders, your measurements should be accurate enough. I have used this method on all types of Ford engines, as well as several off brand engines with great success. This method has not been wrong yet.

 

Thanks this will help me in the future!

 

I'll have to give that a try to see for myself :-)