mongooz
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I'm not surprised by those numbers at all. Lots of cars of the muscle car era were overrated on power, and quite a few were heavily underrated and factory tamed for homologation. 600 HP is reasonable for a NASCAR racer of the era, so the top shelf torino (ford's NASCAR entry) putting down that kind of power isn't unusual.
the actual race cars were making more than that. at that time, they were in the last days of being allowed to run twin 4bbl's and likely a slightly hotter cam.
it was a solid lifter cam with 12.2:1 compression....i HAD to run 100 octane or it would rattle like a snake. we used to go thru a set of yellow jacket plugs every two weeks, if we were crusing it on friday and saturday nights. it would run very smoothly on the street, but it would tend to foul plugs if you didn't get them blown off.
ford figured that putting a secret rev limiter on those (few) models was saving lives, and they were right.
the drag pack cars had a choice of 3.90 or 4.10 rear gears. mine had a trac-lok 3.23 rear gear and a bigger breathing cam than the drag packs, hence the crazy top end.
it would run up to around 52 mph in first, 110 in second, 145 in third.....and well.......4th was all about how much balls did you have.