Use the 1.6 ratio. The P heads flow best when the lift is kept under .500". You may even be better off using the stock cam and 1.7's. At least you won't have idle troubles this way.
send an e-mail to t-moss, he has researched all this gt-40p stuff to death. He has all the flow number etc. so that you can figure out what you need where, and he is always helpful in getting facts and figures and giving advice.
Use 1.6 rockers. The P heads peak out their flow at .400" lift and only flow a couple (literally) cfm more at .500" lift. If you want to fill the cylinder more, first get expert advice from some one like Buddy Rawls or Ed Curtis. It will take more duration rather than lift. P heads flow increases VERY quickly from .100" to .200" and levels out at .400", so design the combo with that that in mind. I'm running 1.6 Scorpions on my P combo.
Use 1.6 rockers. The P heads peak out their flow at .400" lift and only flow a couple (literally) cfm more at .500" lift. If you want to fill the cylinder more, first get expert advice from some one like Buddy Rawls or Ed Curtis. It will take more duration rather than lift. P heads flow increases VERY quickly from .100" to .200" and levels out at .400", so design the combo with that that in mind. I'm running 1.6 Scorpions on my P combo.
Still breaking it in. I've got a miss that comes and goes that I have to track down. The engine got a little on the hot side after starting it, so the TFI may be marginal, or it may need a new set of wires. I'm gonna read the plugs tomorrow. I'll find it.
if you go with longer rockers than are in there now, doesn't that push the valves farther down into the cylinders? if you decide to go with the 1.7s, i would make sure you have enough clearance ... the pistons hitting the valves might ruin your month ...