I dont have an answer to your question, but head over to
www.stangcrazy.com and post the question. That is the official website of the factory stock(pure street and real street)class. The P head is one of the more popular heads over there. I would guess your 30hp guess is pretty close though. I run a set on my car, but they are ported. I also run the standard mac 1 5/8 long tubes and dont have any problems. I do have to use a 5/8 spark plug wrench with the 6 flats on the outside and turn it with a 3/4 wrench, but you can get the plugs in and out with no real problems. I also run the $40 SVO plug wires and even though the boots are close to the headers they dont burn. They are a great head though. If your interested in getting a good head for a great price, call Gerry at BHP (734)455-1905. He sells CNC ported E7 heads that rock. Tell him I sent ya and he will give you the inside scoop on them
. I believe they are $395 with exchange(your stock heads)or $495 outright and free shiping up to $50 per order. You wont be dissapointed!!