Cab Interchange
 

Can you put a 78 cab on a 74 narrow frame truck?

I am putting a 78 f250 2wd cab and body on a 74 f100 4x4 frame. All the holes match up.

what is a narrow frame truck? whats the model? f350?

I assume you mean highboy and the answer is yes. The front mounts will be the same. The back 2 though will need to be re-drilled though since the highboys mounts are on the outside instead of on the inside. At least this is how it worked out for my truck when we did the swap. My swap was a 78 F.150 2wd cab onto a 1976 highboy.

Unless you are putting the cab on a hiboy the frame mounts are identical. The only variation I have found in the 73-79 standard cabs in the Hiboy. In that style (F250 4X4's) the rear mounts are wider. otherwise the cabs all mount to the frame without any issues