You have previously said you don't wanna do glass work on the transom. Has that changed? The 233 is a small enough boat it will respond well to higher prop shaft centerline. But also small enough that with bbc-bravo setup it'll be a boatload of fun with prop where Don Aronow put it 55 years ago.

go into the glass and paint section and read a couple of the transom replacement threads. then you will see why I am saying just put the bravo on and run the beastie...edit: the more I think about this boat, it was really the first purpose-built offshore racer. Don and Co probably did a little trial and error with prop shaft location. It might just be in the best location as-is...

here is about a 10 page pdf on the resto of the orig 233 race boat. including 1 very good shot of where the drive is. if you take a pic of yours from same distance, you should be able to compare heights. this boat was a 409 bbc before the bbc was even called that. Ok, the link doesn't work. I found it by searching formula 233 history in google. There was a post in the hull truth titled "educate somebody who is young and dumb on all the formula 233 variants." 3rd page of thread top post has the link. Link works there.

Since I have to put in a new transom it is easy to raise the hole. I have been told I can go up 2 3/4 inches. With the new props it is suggested that they can work at a higher height than the old 3 blade aluminums did.

there were so many of these hulls built over the years I am surprised no one has info on raising the X dimension.

What do you want to give up ?

Hole shot ?
Top end ?

With the newer props some things can be fixed ,but.

The stock Bravo is a little deeper in the water than the Alfa/R/MR. But it has a lot more drag.

With doing the transom I would go up 2 1/2" on the "X" or go to the short drive.Also I would keep the boat on the light side.

This one had a stepped/pad bottom and twins SBC's at the stock "X" but with Alfa SS's. Mid 70's to low 80's mph. (1987) about 900 hp +-.
Best ugly water boat I have ever raced.

Before you raise it, you need to know where your at. Different hulls like different things. I have been told that a 17" x-dim is a good all around safe bet and can be run with standard water pickups. If your close to that already, you wont gain a whole lot, if your a lot deeper you stand to gain more. And if done right, patching the bottom half of the hole does not create a weak point.

looks like I will try going up 2 1/2 inches