Do you think a 325cc port is too large in a trick flow 270 on a 511 and 6800 shift points?
No. A 270 head should make a little over 700 hp at 6800 on a 511 short block. A ported intake manifold will pick it up another 15 or 20 hp. You'll need a good carb (big 4150 or 4500), decent compression (12:1 or higher) and a good cam. We've built a lot of 505 or 512 engines with 270 heads and they always make 700+ right around 6800 or 6900 rpm.
