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  • December 04, 2024, 01:13:43 AM

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Author Topic: 4.0L Swap, flex plate  (Read 3900 times)

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Offline tgotr

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4.0L Swap, flex plate
« on: October 03, 2022, 03:02:25 PM »
I pulled my 258 and I'm doing a 4.0 swap...well it's been bored and I'm using my Eagle's stock Crank and rods, so it's going up to 4.7L.

I am reading Joshpit's write up, and while mine takes many deviations, it's been quite helpful. I do not have the engine assembled at the moment, and this could be answered by doing that.

Joshpit's write up says you need to use a 32RH OR a 42RE flexplate. Why can't I use my Eagle's stock flexplate off of the 258? There would be many advantages to using it, especially since it's in good shape for being 40 years old. I'm almost 40 myself, and I am in worse shape than that flex plate. I am assuming he recommended the 32RH and 42RE flex plates because he was still using the 4.0 Crank, and I will not be,

Offline R.C.S.

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Re: 4.0L Swap, flex plate
« Reply #1 on: October 26, 2024, 02:06:49 PM »
The flex plate has to be changed if you are running 4.0 fuel injection.  The flex plate has the tone ring for the crank position sensor.
1986 Eagle Wagon
1968 AMX
1966 American

Online rmick

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Re: 4.0L Swap, flex plate
« Reply #2 on: October 26, 2024, 11:25:56 PM »
Another option for the crank pickup is from Hescos if you plan on using the fuel injection
https://hesco.us/products/30791/40l-conversion-parts
72 Javelin AMX
72 Javelin SST
72 Gremlin with 4.0
81 SX 4

Offline vangremlin

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Re: 4.0L Swap, flex plate
« Reply #3 on: October 28, 2024, 12:04:08 PM »
You may want to read through Tougeagle's thread also:

https://forums.amceaglesden.com/index.php?topic=21335.0
1981 Kammback 258 - "Pepe"
1980 Coupe 258 - "Ginger
1972 Gremlin X 304
1978 Gremlin 4 cyl 121 - sold
1964 TBird 390 - sold

 

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