I forget right now (made that change 17 years ago), I'll have to take a look again.

Yeah I know what you mean about the 'Project' always evolving... been there!

First of all, I have never heard of anyone spacing down a TRS drive. It pretty much has the longest distance from input shaft to prop shaft of any drive ever made. Second, as far as I Know the vertical shaft doesn't allow a spacer to be used.

You can add spacers to TRS.

I know there used to be extension boxes for them, but they're few and far between now.

If you're going to run the merctransII trannies, look up KC marine in washington state. Talk to Kirk, he's very knowledgeable on these trannies and the TRS drives. He makes modifications to the merctrans to make it handle the bigger power. The merctrans also takes less HP to turn than the borg warner.
Mine have been bulletproof (except for the one I dropped and busted the case on the floor, and tried to fix myself lol)
You will enjoy the extra room in front of your engines. You can actually stand there.
They will handle the non recommended holeshots too.. (only did this once)

https://youtu.be/VMLeElqcnYA

Here is some info from bluethunder dave I got years back. Probably had one of the fastest panthers

94mph is my best to date. 90-91mph is generally achieveable. The big helpers from 62mph to 90mph were, raised x dim 2", built stout 650hp blower engines, ground some of the hook out of the hull. Nose cones helped too. And yes, a good 3'chop makes a big difference although a bit of a wild ride at those speed. Which friend of mine were you talking to? Congrats on the new boat btw. One disadvantage you will have over my panther is I have bravos which are faster than ts drives.

Dave
I needed a new transom so when that was done I cut it 2" higher. My propshafts are 4.5" below the hull. I run 4 blade bravo1 props 32p spinning in at 5300rpm or thereabouts.

WHat kind of price does it cost to get 2 of these built? I'm getting ready to junk my baby velvet drives, for the bigger ones, but this sounds interesting. I actually need to move my engine a inch forward to run the larger drives.

500+ you should see between 75+ Mirage 3 blades 25P. 550+ 27 Mirage 3 blades around 80mph. A labbed 27' Mirage is what I would run if I was still investing in my Panther. I run around 80, Bravo boat is much faster.

Sorry I didn't see this post. Seems like they were between 8-1000 apiece depending on what they need. Google "kc marine trs" and go to the website. Call kirk, he's the guy who builds them. I think he's a one man show. He'll take the time to explain everything. One big thing is dump the trans cooling water overboard instead of out the exhaust. It increases flow and let's them run cooler. Also running amsoil synthetic fluid is good for them. Private message me if you need anything else.