Weaver E8 shells (on MTH chassis?)

Even if the molds are not related, you can adapt one to the other, probably with minimum effort. The precise length and width of the frames and bodies will be a factor, but as they are both good scale models of the same prototype, the length/width issue will probably be minimal. Modification is possible.

Mounting points and other things may have been modified, even if the molds are indeed related. Adding new body mounting posts (using square styrene or basswood) or drilling new frame holes is not a big hurdle, especially the frame holes.

There may be issues, but none should be insurmountable - that's model RR'ing. Heck, they may drop right on the frames.

This is a Weaver E8 shell on an MTH body. 

I never bothered to screw it down and can't recall if the screws lined up, or were the exact same length. The shell definitely just plops onto the frame though. No size problem at all.

If you want to do this, there are no real difficulties. When I got my 3-rd Rail E8s, I lost interest in the Weaver/MTH combo. 

This is a Weaver E8 shell on an MTH body. 

I never bothered to screw it down and can't recall if the screws lined up, or were the exact same length. The shell definitely just plops onto the frame though. No size problem at all.

If you want to do this, there are no real difficulties. When I got my 3-rd Rail E8s, I lost interest in the Weaver/MTH combo. 

Another shot of the Weaver body atop an MTH chassis.

Thanks

I actually found a set of MTH E8s I forgot I had (bet I'm not the only one that has done that) and compared.  Everything is the same.  Only difference is the mounting screw length.  Just keep the MTH screw with the MTH body and the Weaver screws with the weaver body and you are good to go.