I am trying to find out if the Evolotion 58GX will fit in my 300S Wagstaff without firewall mod. The 58GX drawings in the manual are not clear. Can someone tell me what the length is from the firewall to the drive washer (back of the prop). The engine specs say the mounting length is 243mm. From the drawing, I think the dimension I am looking for is 245-55mm, 190mm.