Any up dates?

This is a cool project, but I think that you are going to want to rethink you throttle linkage. It is going to really screw with you on idle speed.

Air cooled motors grow when hot, and the Type IV can grow somewhere close to an inch in width from cold to hot. That is gonna change the length required by that cross rod.

It also explains why the linkage on a 911 engine looks like it does, with the crossbar that pivots.

A whole inch????

I think that's stretching it a bit.

I got about 1/2 inch from a full blown 13:1 race motor.
Made me change linkage.

A stock motor moves less than 1/4 of an inch.

And yes, I have measured both race motor and stock....cause I was curious.

I also have owned every cross bar linkage made, and a few of the center types...
Ended up with Foleys cable setup.

I even designed a cable setup...

The motor does move, and cable linkage is the best answer.