Otay, I must put on my 45power binocular's I call glasses and read the fine print.....It's,,, from the back of the Supercharger to the prop washer it's 120.7mm ...the mounting hole's are 25mm x 52mm center to center ,and from the center of the forward mounting hole to the prop washer it's 57mm.... the engine case is 43mm wide ( not including the mounting tab's) and 21.5mm from the bottom of the case to the bottom of the mounting tab's with a overall height of 124mm top to bottom..... Sound's like the 4-40 rod idea will work quite nicely I must add that to the list of mod's the 2nd UCD3D is getten ....I'm so glad I thought of that....HAHAHAHA. You won't be disappointed with the YS ....WOWA RED ALERT!!!!!!!! ...I just went through the note's I made when I built the 1st UCD3D and I mounted the engine at 6 and 1/8" from the fire wall instead of the 5 and 7/8" the manual call's for !!!!!!!!! I did this because the cowling didn't line up properly as per my note's ...I must go outside and start kickin my own ***** for that mistake...B right back.....Okay there.....I must sincerely apologize for my error....JW