AMC 4.0L in a 39-47 Dodge/Plymouth

[Richie15]

Hi, I am looking for help with anyone done this engine swap. Measurements of the compartment from the firewall "nitch" to the backside of the radiator cores would be helpful too (my cab with doors is in a body shop) so I can't do this measurement right now, maybe a couple months when my body guy gets to it.

I like my Cherokee inline 6 & auto tranny, tough, dependable and could do some hauling, light towing in my 1940 PT-105. So I am thinking on these lines of mounting this drivetrain into this pickup. Also, a modern engine would be best "today" as my daily drive.

I would appreciate advise.

Thanks, Richie

 

[greg g]

LookI believe the Jeep engine is on of the longest out there,  9 or 10 inches longer than the flathead.  Pretty sure you can get some of it back with different fan set up.  But I think some firewall mods are going to be necessary.

[TodFitch]

Been a while since I've had the vehicle, but I recall measuring the length of the 4.0L in line six in my old Cherokee and finding it several inches longer than the 23" length of the engine in my old Plymouth. I suspect you will have some considerable modifications to get the 4.0L engine into your PT-105.

[B1B Keven]

29 1/2" from the 'nitch' to the radiator holding the tape about 5" above the head of the flathead. Are you going to use the AW4 auto?

A Comanche automatic steering column might work.

There are kits available to stroke the 4.0. All the way to 4.6 litres.

[Richie15]

Thank you Kevin, yes with the AWA auto, shifting is in my taste!

     This is encouraging as my 4.0L is 31 inches....possibly enlarging the nitch debth a few inches will do it. My measurement of the 4.0L included the water pump but not the fan as thinking electric fan there but more nitch debth either way.

     I have not find an aftermarket firewall "nitch" pre-fabricated yet as I have anticipated some increase there, maybe 5 or 6 inches would do it. I would have to look at steering column issues, maybe the stock would clear...I would like to get the tranny shifter off the floor/onto the steering column, is the Commanche shift on the column?

Regards, Richie

[B1B Keven]

I 'think' you can move the radiator forward. Yes, the Comanche shift is on the column.

 

Another thought is an XJ/MJ 2wd front axle. Disc brakes and the correct bolt pattern.

[Richie15]

Thank you all, some delays in this project (what else is new?) but, last week the cab and doors media blasted then taken to a body man. He is going to epoxy primer then look at firewall modification to set back 5" or 3" (with engine coolant fan in front of the radiator) and all the other dents and fix one of the bad lower hinges. His ideas will be considered for sure.

Me, I will clean up the frame, especially where the cab mounts so that when he is done I will take toe frame to his shop and we will set the cab on the frame.

Getting all that accomplished I will have the fun of measuring, figuring the engine/tranny mounts on this old frame, drive train aligned properly...major moves forward....wish me the best, an of course: all and any suggestions.

Best Regards

[Jomani]

Sounds like a fun project. Where are the pictures?

 

Keep in mind that the automatic transmission will also be longer and taller than the original drive train. The 4.0L has a rear sump oil pan which is perfect but will also limit how far forward you can move the engine. It is also much taller than the Flathead. If it were me, I would mock up the engine and trans in the frame and get some good measurements before cutting into the firewall. The 4.0L engine is probably one of the best things that came out of AMC (great torque) but certainly not plug and play in your application.

 

 

[Dave72dt]

Since it's already at a body shop, I wouldn't go any further than primer before you start fitting in the proposed drivetrain.  I can only imagine the damage to fresh paint when trying to fit that drivetrain in.