Depends on what you call decent, my 340 ran a flat top with a 55cc chamber aluminum head. It was 11.4-1 and ran on pump 93. With the same heads and a 21cc dish my 408 was 10.8-1.
That's what I would call decent.
But your 2 different builds reinforce what I said previously. A stroker build allows much lighter weight Pistons and makes it much easier to get a high ratio without a big heavy domed piston. The 55 cc chamber helps even more. Your dished stroker piston Will be way lighter than the Op 13:1 domed piston because the stroke increase allows this with more swept area.
That is also why yellow rose is saying that if the Op bought new Pistons for stock stroke build with the same length rods and stock piston pin height, they will still be fairly heavy because the piston will be much longer than a stroker piston and cannot be dished with a 70cc head. You also have to remember that aluminum heads at the same compression ratio make less power than cast iron,
11.4 is really 10.4 which takes us back to what the intended goals are.
