Bore notching = 25 to 30 HP on a 454, less on a bigger bore.
Jim Valakeo did a back to back test on a dyno. I don't know what the build was on the engine. Obviously not stock.

is notching basically tapering the top of the bore to accommodate for the valves?? funnel effect essentially??

If your adding a bigger blower, cam and heads, and the build was properly thought out, your around 650 give or take with a lot more torque, time to start putting that money towards spare bravos instead of trying to squeeze 10 more hp out of it,

an upgraded outdrive is also part of the build

Bore notching thread. From what I’ve read there’s no reason not to do it if possible.

https://www.offshoreonly.com/forums/...-notching.html

cool thanks!!