According to an article I was just reading, the GT4 mustangs engine is tuned by Roush Yates engines and features a Cross plane crankshaft. It’s also a 5.2L. But I can’t say after doing a quick look if Ford actually raced the FPC version of the engine.
This information came off the website Auto Action which is Australian based.
https://autoaction.com.au/2019/06/01...4-pony-express