Hugo, lots of guys like the 540, and they have good reason. It is about as big as you can go with a low deck and have a reasonable piston pin height, piston skirt still up in the bore to keep the piston stable. A local racer ran a 540 b1mc about 20 years ago, and made over 1000 reliable hp. And i think the reliability is what you will find out is the difference. Trust me, go for reliability. I didn't and spend way more time working on my motor than racing.
If it were my motor, i would go 540, B1Mc ported heads, and a cam custom ground with the intent of giving away the last possible 20 to 30 hp in favor of a cam that is VERYeasy on parts. You will probably be running this deal to almost 8,000 rpm, so plan for it to make it live.