Paul
If you are running on the salt, I can help a little.
I am the guy that designed (redesigned/reworked tooling) for the Ford SVO block. 200 parts were made in Brasil and shipped to the US. I believe a few were retained in Taubate and became engines in off road "Raid" vehicles.
If you are running on the salt and want to run 1000+ HP you really need a block like this, and the most robust bottom end that you can possibly create. I am very familiar with the Ford turbo 4 community and really respect the exploits of the 2.3 crowd.
BUT
they are street and drag racers, not running flat out for 5 miles.
LSR and Boat racing are the very most severe applications ever for engine reliability and durability
Your goals put you in a really special category
The SVO block I did in 1989 basically was a siamesed bore, thick bore walls and thicker deck, along with lengthened bolt bosses for less bore distortion under very high cylinder pressures. Skirt thickness was also increased. I ran billet main caps but still limited to 2
half inch fasterers. We had porosity issues in #3 bore because we were casting them in production flasks, and by adding 25 pounds of iron we changed how the iron freezes when cooling. SO, some of those blocks had air bubbles that are exposed when going to something like a 4" bore that I'm currently running in a N/A motor. I still have 2 blocks, but not for sale, but since Dan Esslinger remade and improved with the RACE block I would pursue one of those and design a girdle like Esslinger uses in the midget engine.
Is your head an XT BB. If so why not a Billet block and girdle. The could even redo the machining program to increase sections where
needed. A good billet Aluminum block would be great.
Tell us what you are racing and what kind of class requires a carb.
Are you running methanol