omc compatible engine mounts

i want to know can 3.0l omc mercruiser mounts be used on a 3.8 omc mercruiser engine(that is inline 4 cylinder on a v-6). i want to swap out a 3.0 for a 3.8,the stern drive on my boat is a cobra 400,the 3.8 is in a boat with a cobra 400,so i know that the 3.0 is not matched to the boat i own(not sure why,it was inherited from my brother,last year)so i want to find out if i can change them without having to get engine mounts,any and all help would be extremely welcome
ps, be patiant with me ,i am new to this

you would need to fabricate the stringers/ motor mounts to install a V motor.

Look at the front of the 3.0 see it is mounted at a single point.

See the 3.8 it is mounted in the front on both sides.

See the 3.8 has a y pipe, the 3.0 does not.

You sure you have a cobra drive ?

What year is the boat ?

See if you have a stringer it is a whole different story.

So if you have rams on the drive it's a cobra.

No rams and a big round rubber seal on the rear it's a stringer.

both outdrives say cobra 400 and are identical,the mounting plates on the inside hull are the same,and they have the big rubber gasket that you say makes them a stringer.my concern is if i can use the engine mounts on either one,they look interchangeable,but would like to know before i try to swap them
will take a couple of pics in the morning,it is dark here now and the pics should help to explain what is in both better than i can

OMC never mated the 3.8 to a 400 series drive, or a Cobra. The 3.8 was only mated to an 800 series stringer drive. The 3.8 was discontinued 2 model years before the Cobra was introduced.
400 series (13 spline propshaft) lower units are only good to 140HP. The 3.8 V6 was rated a conservative 170HP and 185HP (2V and 4V)

The engine mounts are different as night and day as people are telling you. I don't know what you're looking at, but the 3.0 uses a cradle at the front of the engine. The 3.8 used hydraulic trim rams for front mounts.

Maybe a photo array would help you get some info about what you have there.

Yes pictures, motor front and side.

And the drive sideways.

Look at the transom outside upper right hand corner and the last 2 numbers will give us the year.

We await your post.

it is a stringer,and hopefully these pics will help

both motors have the same outdrive

But one is a 800 and the other is a 400. They look the same, to the untrained eye.

Look at the" bullet "the lower housing.

What years are the boats ?