Need help determining what prop I need if I were to put a bravo one with 1.65 gears on a 88 formula 242 with a stock 454 ?? Wot rpm is like 4600 I believe

I'd start with a Bravo 1 24" four blade. A Revolution in the same pitch might work as well.

I was going to suggest a lab finished 25 4 blade Bravo to start. I would contact BBlades, they have props you can "rent" to try out and will also help you determine what prop is best for you, real nice guys, I believe the owner worked for Merc Racing for years, really knows his stuff.