218 to a 251

[bhoward]

Good morning all,

 I have not been on here in a while, sorry for that. I have not messed with my car in for a while. I spun a rod bearing in my 218 and haven't run it lately. I now have access to a 251 ci  C38 series. My question is will the bell housing, flywheel, and 3 speed transmission 218 bolt to the 251. I am not sure if it has standard flywheel or an automatic flywheel yet. I haven't  been able to gain access to it yet. I am also wondering if I should just rebuild the 218 so I don't have to get into fabricating motor mounts and trying to match the tranny and bell housing together. Any advice would be greatly appreciated.

Thanks 

[greg g]

Suggest you do a search for Don Coatney 's thread where he documented with photos, putting a 251 ibto his 48 p15 sedan.  There were some issues concerning the thicker crankshaft flange of the Desoto engine.  He figured it out, but it wasn't a straight bolt in.  Some finnageling was required.  There was also an issue with thr front crossmember. Again not a bolt in but easily overcome with torch and welder.

 

Unfortunately  Don passed away a year or so ago, Don would have been glad to have talked or messaged you to and through these speed bumps.  So his pictures and words are what's left of his process.

Edited November 16, 2021 by greg g

[blucarsdn]

For the most part it is quite simple to install a long block 251 CID engine in a vehicle that came with a 218 CID. Many of the early Dodge'/Plym frames were drilled for the 25" engine by the factory because it was quite common for the smaller Plym/Dodge chassis to be sold as Chrysler/DeSoto in foreign country's. I put a Chrysler Spitefire into a 48 Dodge I have, just required moving the radiator to the front of the core support. I did not have a trans issue because the Dodge came with the Fluid Drive which the Spitfire had so i used the Chrysler trans.

OK, having said the above, you might want to consider having the 218 rebuilt. Rebuilding the 218 lets you start all over again with everything new and stock in lieu of installing a used engine with doubtful history. wm.

[James_Douglas]

Don was a great guy and his work was top notch. Review his threads and you can do what he did.  We had a lot of fun when he visited on a couple of occasions. He was great to bounce ideas off of.  Channeling Don !  Channeling Don!