So here is a picture of the back of my boat. The boat runs out good @ 28mph WOT and doesn't porpoise at all. My issue is when I get shallow the prop is so far below the bottom of the boat it starts to dig real bad. The boat is good the way it is but after looking at other friends mud boats it looks like their lower units are almost parallel with the bottom of the boat. The boat is a 1542 Lowe Roughneck. Any ideas?

I am almost 100% positive that, that motor is a short transom motor, and your transom is tall.
Measure your transom, it should be around 16 inches if that is indeed a short transom motor. It looks like your transom is around 19-21 inches. If so, cut down your transom to around 16 inches or so. Surface drives are meant for the prop to be at the surface of the water. (half in the water and half out)

And, looking at the motor and transom, I am also almost 100% that your speeds are bullshit too...

Report back to us after you have measurements!

Come on man you know all them small blocks run 28. We all just stupid for getting them big blocks and putting thousands in em to run 28-30.


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Indeed it is a short motor. I just went out and measured the transom on the boat and it is 17". When I bought the motor I remember debating on which way to go and went short. The speed I posted is accurate but that isn't what I am interested in debating. It is a Subaru 28HP mini. If your familiar with the mini it has a trailer position on the trim and in that position it looks good, just a little high. I remember somewhere hearing about shims you could install to get your angle right?

And don't worry, I can't keep up with my buddies 35 GTR!

No, you don't need to install shims.
You need to cut down that transom IMO.

Also, how much more can you trim down your motor?
Post a picture of the motor trimmed all the way down.
And if that transom measures 17 right now, id cut it to 15 or so.

Trimmed up all the way in that picture?

Also not to get off topic and a little bit of advice from the pic. I would try to get the back of that boat up on the trailer farther.. unless you want a hook in your hull from the weight of the engine forcing down when transporting. Just my 2 pennies

Thanks for the tip on the trailer. The back is just even but I'll pull it ahead a touch.

Looks like the Charlie Brown Christmas tree behind your motor

Here are a couple of pics with the motor trimmed all the way up.

Did you measure the transom on a right angle, or just throw a tape measure on the metal?

The following info is from Mud Buddy

Short Transom motors are designed to work on transoms that are 15" to 17"

Tall Transom motors are designed to work on transoms that are 19" to 21"

Preferred transom angle should be 17 degrees

At one time Mud Buddy offered a shim that helped correct the angle if you had a boat that didn't have a 17 degree transom angle. I know that these were needed on the War Eagle boats.

I just put a tape on the transom from the top to the bottom. I talked with Mud Buddy and we figured a long will be to long as well. I think I'm going to look at modifying the transom to get my drive more parallel to the bottom of the boat. I probably should leave well enough alone but its just aluminum and wood so what the heck! I'm also going to hack out the rear bench so I can stand proper while I'm at it!

Done that before

I dont know nearly as much about boats as some here but do you think you should fasten your kick braces to the ribs or maybe even weld a bigger piece of plate under them if you are going to leave them there to spread out the load?

I thought about it. If I had planned on keeping the boat long term I would have. Figure it was stronger than the rotted wood core that was in there, plus it had a heavier motor on it before I bought it and redid the transom. Haven't had any issues with it.