I'm Not Fat!!!
Stallion said:
An estimated driver's weight? Hmmm....
Oh...wait....you didn't really MENTION me...did you? :L
3500 is about right (mine's a '75 ragtop.) I used some private truck scales (they charged me $15 I think...) not long after I changed the front and rear suspensions and some other parts to see how they affected balance more than anything. I don't recall the spec now, but it was around 3500 - more importantly I was stunned to see I was within
one percent! of 50/50! It was like they INTENDED my fatass to be in that car!
Sorry guy, vettes are strong, heavy cars with solid frames. They have good drag coefficients and nice low COGs. They are a nice solid frame and body design that don't bend apart like monocoque cars with higher power and hard banking, but they are not super light. Our '75's had some weight
adders too, like much heavier doors. I've heard of skeletonized ones, even with decent roll cages, getting into the 2600-2800 range, and still (sort of) being drivable cars, but much more than that and it gets brutal.
The trade off is you can easily put in a nice, new monster displacement 700hp mill and everything except for the rear end takes it fine.
That comes to the really bad news - forget comparitively heavy weight, you're REAL problem for drag is the otherwise great IRS. The center is only a 10 bolt - I think all the '75's were at least Dana 44's but some were just Dana 36's. Because it is nonmoving and heavily bolted to the frame it really is stronger here than it would be on a normal dead axle car (like that TA,) but it still isn't that strong - and the halfshafts, especially the U-joints, are a common point of failure. I feel this was one key design shortcoming - going with a much heavier 12 bolt, Dana 70, 14 bolt or whatever GM had sitting on the shelves then, but the weight of those units was felt to be unjustified.
Still you will tend to grenade first the outter half shaft U-joints, then the inner, then the center section itself, then twist the halfshafts themselves, in that order of expected failure. There are upgrades available for all of that that will handle the power, but they are pricey. At least few ever damage even the lightest of the main driveshafts - unlike on other designs, they simply aren't normally known for failing, since they hardly move (angle wise) at all.
I have the Tom's Differentials 12 bolt conversion (a newer better one is now available from them) but have yet to get the "1480" 0.135" wall thickness halfshaft kit. Van Steel and Dragvettes also make nice lines of upgrade products, including some exotic material halfshafts and driveshafts. Even the best stock design big block setup help quite a bit but are still likely to grenade under hard standing launches.
Until you upgrade the 165hp L48 mill though, it won't be too much strain..
Oh, and none of this hits on the geometry changes under a launch with the IRS. The squatting down effect isn't that bad in itself - much better than wheel hop on dead axle designs, but untill all of this is controlled with better springs and shocks and the right rear sway bar (or none at all) the change in angle of the tread to the ground in that condition causes some problems in getting the best hookup.
Vettes are all around sportscars, capable of stunning handling and controllable at really high speed driving - yes, even C3's (especially with a limited number of key upgrades) - and with great acceleration rates with the REAL engines you can easily put in them - but they are not the ideal 1/4 mile all out, undrivable anywhere else, 10 runs before major rebuild drag car.
They can be modified to be good at that too, and many have, but it costs.
(Please don't hack out the IRS and put in a dead axle! Some HEATHENS do that too.... :L )
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