75-79 258 wiring differences?

[Calvie]

So I just started investigating my new eagle.
It appears I have a replacement motor. Judging by the 3227445 block casting it's a 75-79 motor out of lord knows what.

My question is... Are there any major wiring differences?  I pulled the wiring diagram off of the eaglepedia and started to try and connect the dots, only to be more confused.

Also, the PO has a toggle switch running from the dash directly to the ignition coil. Any suggestions as to why?

[mudkicker715]

the front axle will not bolt to that year of motor without major modifications to mount the axle

[Amc1320]

Hi calvie,

A 75 to 79 engine wouldn't work in an eagle, unless it was very very late 79 and was originally used in a 1980 eagle. The block castings were changed to add the two bolt holes toward the rear of the drivers side of the block to hold the front axle up.

There were a few other changes but that's the major one that you can use to easily identify a pre or post 1980 amc 258 engine.

[vangremlin]

I looked at the picture of your engine in your other thread, it definitely looks like a pre-1981 engine because of the valve cover.  But the guys are right, it would have to be late 79 or 80 engine to be able to accomodate the front drive components.

[Mernsy]

Where did you get that number? I'm pretty sure it's a head casting number, not a block number.

Here's some info I found.

Build Date Code
The engine Build Date Code is located on a machine surface on the right side of the cylinder block between the # 2 and # 3 cylinders. The numbers of the code identify the year, month and day that the engine was build.
Explanation Engine Build Date Code
Example: 3 10 C 11
1st Number Character is the build year: 3 = 1983, 4 = 1984
2nd and 3rd Number Characters is the build month: 01 = January, 12 = December
4th Letter Character code indicates the engine: C = 258 CID / 2v Carburetor / 9.2:1 Compression Ratio
5th and 6th Number Characters is the build day: 01, 02, 03 up to 31.
The example code 3 10 C 11 translate to: 258 CID (4.2 Liter) engine with 2V Carburetor and a 9.2:1 Compression Ratio, built on October 11, 1983.

[Calvie]

So after looking this morning, I see I've got a date code of   1 11 A 15

I guess that makes it an 81?

I was hoping to chase down all the wiring this weekend, but my wife just signed me up for some social function I didn't know about. Hopefully I'll still have time

[BenM]

The colors may change, depending on how much wiring was brought over, but fundamentally the engine is the same. The engine harness comes out of the driver's side of the firewall and the computer harness comes out of the passenger side of the firewall, they're almost completely separate but for a few power connections.

Do you have an aluminum or cast iron intake on that car?