Any help please

[ebko]

Yes I have a 1977 Ebko trihull that I had to replace the engine bay because of rot and I didn't think to measure the mounting holes for the omc 140 engine and the Stern drive if anyone could tell me how to proceed with getting the right placement I would be so grateful thanks

 

[Droid]

Well now, you are in a pickle but I don't think it's insurmountable.

The rear motor mounts are some easily measured distance apart. I don't know if that distance falls within your bilge or would land on the floorboards. You measure & decide.
The clamping surface of the transom seal needs to be approximately equal with the transom. Too far forward & the top of the drive will hit the transom when tilted. Best to tilt drive & verify clearance. Then plan on that fore/aft placement.
Forward mount is the "A-frame" at front of crankcase. Regardless if Selectrim or fixed trim, it's placement will be easy to determine.
The mounts need to be the height to get cavitation plate flush with & parallel to the bottom. The forward mount height will adjust your trim angle regardless if fixed trim or Selectrim. Better to be a bit low & add shims if necessary.
Remember, your drive pushes the engine & not the transom. The mounts must be strong (as in properly glasses into the boat) or you may be finding yourself with an engine under your left elbow.