sounds like you got a good combo planned out, (mainly becuase i suggested some of it
)
but i dont think its gonna be too easy to find those older heads in a junk yard
one word, 2 syllables..... Ebay
i'd try to find some GT40 (not the Ps) just because you have to get different headers with the P's, but since you dont have headers yet anyway don't count them out
you could find some heads for a pretty good price on Ebay, as well as a cam, i found my B cam on Ebay for $100 (came with a timing chain too)
if you drive the crap out of it with good traction it could be a 12sec car
about the gears, 3.73's and 4.10s will both give a great improvement but the decision lands in how much highway driving you do, you've probably read numerous posts on which is better, if not search for it and read up on it
and to save some money, go to a local ford dealer service dept and try to find their mustang gear head, (every ford shop has atleast one) and see if he'll do gears for sidework, the ones i know of will do it for around $100 opposed to $200+ at a shop somewhere
oh yah about the 16 year old thing, be glad you even have a stang at that young, i had to wait till i was 17
if you plan on going to college then get as much done to your car as possible BEFORE you start, im in my second year at a very expensive engineering school and i have no money to buy anything for my car, good thing my b-day and christmas are coming up!
really sorry i wrote so much
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88 Notch, B&M Ripper, 3.73's, Ported E7's, Explorer int. w/ ported lower, pulleys, 1.7RR's, BBK headers, off-road H-pipe, flowmasters, subframes, 65mm TB, March ram air ,MSD coil, U/L control arms, 155lph f/p, Crane Adj.FPR, Nitto drag radials, best 1/4--> 13.76@101.4 on a 2.17 60ft