Swing engine mount vrs welded to frame

[Tommykart]

I'm trying to find out witch is better and why. I'm restoring a 1961 Rupp Grand Prix kart. I'm at the point of mounting a predator 212cc on the frame. The kart originally had a swing engine mounting, but I'm thinking a solid welded to frame might be better. Can anyone help with this decision? Thanks

 

[anickode]

A fixed engine mount will not work with a spring rear end unless you use a jackshaft that is on the same axis as the pivot point.

So if you want suspension, you either gotta use the existing or do a bunch of modifications. In theory, the fixed engine is better because it reduces the unsprung weight on the vehicle, but it's just not practical for a go kart.