Which would you prefer in a 31ft formula and why?

420/trs or a 454 mag (365hp) with 89 bravos

365 with bravos. I had a 292 with that setup. The bravos are easy to repair/replace first and foremost. The 365 motors can have their performance increased as they have rectangle port heads and forged internals. You need crane gold rockers, intake, carbs, and exhaust manifolds and you could be close to the same power. This is basically what I did to my formula when I bought it. And remember, TRS transmissions rob power so both boats side by side might perform the same.

I have a set of 420 (blowers) available to me. Would either accept them better then the other? I'm looking for a reliable setup.

The 311 I assume you are asking about is a great boat with the 420/trs setup, it is better balanced, with that being said the 365/bravo is the way to go based on parts availability

Im running a 365 hp/bravo setup. Could you be more specific about intake, carb and exhaust upgrades?

Exhaust I used EMI but I like stainless marine manifolds better and if I did it again that's what i would buy. I kept my quadrajet and fattened the secondaries. And put them on dart intake manifolds. Pushed the Formula to 72 GPS. Just ran well all around. Fun boat. Ran 9.5:1 compression, so don't think they would be viable for blowers with changing pistons but I don't really know.

what year 31 formula? i assume it is a TRS boat now? it is a lot of doing to do the transom and relocate the motors. unless boat needs-is getting a transom anyway, it may not be worth the trouble. just curious; how much is a pair of Konrads anyway?

Looking at diff boats.

in that case, bravos. the only justification for TRS is they are already there and paid for and it is a ton of work to convert. unless there is big price diff between the 2 boats there is no contest.

The Merc 420 is the base for the 525sc with the addition of a 177 blower. I'm not saying just bolt the 420's and go though.