ok thanks this is good info.. The two sets of heads I have are 781 and 049 oval ports. What do you think of these? My rods are Eagle H beams 6.385. I will get a Lunati 4340 4.25 crank soon. With the stock heads what advice and what HP can i see with these? Is there any issues with too much crank case pressure when running high compressions? Thx