Good luck. Bob ran 5.82 shifting around 8000 with a 904. Broke it due to an incorrect rocker length. He ordered JE billet dome pistons hoping for more hp.

I assembled and ran a glide. It liked shifting at 9200. But, ran the same et and mph. I talked with several builders of R5 engines. They all found domes to slow the engines down.

Hopefully you will have better luck.