Carbs build question

[mac383]

I want to build a 7 petal 2.5 with carbs.
What carbs and jet sizes should I use?
what would I have to do to a 200 block to get 245 hp like the carb offshore?

Many thanks

[David - WI]

There's a little bit of carb info and some great reed/intake info from T-Rex here: https://www.biggerhammer.net/mercury/

[OnPad]

Wh-20 carbs

Thinkin this is a 260 port map.

[rjdubiel]

with WH carbs start in the mid 80's for mains, I ran 56-62 idle jets. My 2.5 245 carb swapped to WH series carbs I started in the 90's and got down to high 70's. Be careful as if you just run the river at half throttle, there is a lean spot in the mid rpm range with WH carbs.