RE: MiniMental is back once more!! Speedmaster .21
Aidan,
did you have plans/blue prints with your speedmaster hull?
those plans will tell you roughly where the engine should be mounted.
your stuffing box would come out about 1/2" more or less inside the hull and about the same outside (under the boat). Than your stuffing tube will slide inside the box and be approx 3/4" from your collet. enough room so you can easily remove the collet without having to take the engine out.
if you didn't get any plans I believe the best way to find out where to put the engine is to have everything mounted first, Strut, Rudder, trim tabs, fins, radio box complete and fuel tank (empty).
Than you can drop the engine in and move it forward or back to find your CG.
Dan.