Yep-you have some decisions to make. a .30 over L28-even with dished pistons will be high CR. IMHO, with no quench in dished pistons, it might not be the best option. Might need to much timing pulled. I think flat top L28 .030 over would put you around 11 to 1 , not sure what dished pistons would be. L24 will be fun and I run full timing with that set-up. Maybe not as torquey as the l28, but I got 155RWHP with SU's. Like said-you will need to modify the block for bigger valves, but you can do that yourself.