Does anyone know if the 1974 F250 and F100 frames are the same dimensions? Curious for IFS conversion.

 

They are different thicknesses for sure but I'm not sure on other dimensions.

 

As far as the 2wd versions are concerned they do have the same dimensions. 4wd's are a whole different story. The frames are completely different. Not sure what you are meaning when you say for IFS conversion though. They both already have IFS on the 2wd. They are known as twin I beam front suspension. Unless you are talking about doing a Crown Vic front suspension swap. As far as frame thickness is concerned. I have heard this rumor for years. I personally have never seen this to be true. One example I'll give is several years ago now I purchased a 1978 F250 4x4 as a parts truck from a local towing company. I needed some things from this truck to use on my 1978 F150. One of the items that I ended up swaping ove to my truck was one of the front cab mount brackets, and the rear cab mount crossmember. As some here may know the rear cab mount cross members are different from an F150 to the F250. The F150 the crossmember rivets to the upper lip of frame rail and also to the side wall of the frame rail. The F250 rivets to the upper and lower lip of the frame rail and not to the sidewall. However, the f250 crossmember swapped into the F150 frame perfectly. I've also heard of guys using the TIB arms from a F150 and using on an F350 and swapping the out knuckles over for the 8 lug conversion. And vice versa.

 

There are posts on this site about Ford published literature for the frames. It may be in search. It pretty much covers the dimensions for everything.

 

Take a look at this post for the details: https://www.ford-trucks.com/forums/1...l#post19652916

The original source: https://www.fordification.net/tech/bodybuildbks.htm