A few years back, a series of dyno tests were done here on both a 292 and a 250. The 292 made 300 HP N/A with 8.8:1 compression using the stock open chamber head. If the LPG pistons can give you that much, it will be all you'll need. Milling the head excessively creates other issues that can add up to more costs and might even end up being more than a set of pistons by the time your through.
