Toronado
And how about for the base Camaro the 4.2L I-6 instead of the crappy Buick V6 (though the Caddy 3.6 is a pretty spry engine), and for the Z/28 the Northstar 4.7 as an option?
There are a few problems here:
1) The votec 4200 I6 isnt available with a manual transmission option like the DOHC VVT 3.6L V6 (255HP) out of the Caddy CTS, which has the 6-speed manual transmission. However, the engine is very expensive and is really only in the higher class models like the LaCross, Lucerne, CTS, STS, SRX, etc... There would be a greater chance of the 3.9L V6 from the Pontiac G6 to be adapted to fit an RWD vehicle as it is cheaper, only has ten fewer horsepower (240), and will probably last just a bit longer. But it is a tough call. GM probably would try to use as many adaptable parts as they could, and being that the 3.6L V6 is used in the Aussie Monaros and Commodores, it just may end up showing up.
2) Using the Northstar would never happen. The Northstar engine program was origionally supposed to be exclusive only to Cadillac and Oldsmobile, but when Olds dropped out, the torch was passed to Buick, while Pontiac got ahold of the 4.0L V8 for a short time in the Bonneville GXP. The engines are extremely expensive, heavier, overall larger, and put out less horsepower than the Vortec 5300 and LS2 V8s. The Z/28 was supposed to have a race-preped engine capable of reving up a bit higher than the regular-grade 350, and by placing the 283 crank in the 327 block (with a few other minor differences), you got yourself a 302...Yes, it had less power than the outstanding 327 (the actual displacement of the 5300 V8), but it proved itself on the track over and over again... Chevrolet did produce a modern version of the 302 based heavily on the former LS1 V8, but they only built one, and place it in a Camaro Z/28 showcar. They could do it again, but it may not be powerful enough to compete with the new 300HP 24V 4.6L Ford V8.
Toronado
The Camaro has never hurt Corvette sales before, even when the Camaro was faster than the Corvette, like in '67-'69 with the original Z/28. Only a few Corvettes could touch it, and they all cost about the same.
Thats a bit untrue. The Z/28 was faster than the 'base" V8 Camaros, but not nearly as fast as it's SS sisters, or it's Corvette sibling. The DZ 302 was underrated at 290HP, and was capable of pulling a 0-60 in 7.4 sec, 1/4 mile in 15.12 sec @ 94.8mph in 1969... Compare that to the 1969 SS 396 with 375bhp, capable of 0-60 in 6.8 sec, 1/4 mile in 14.7 sec @ 98.7mph... The fastest Camaros were of course the infamous COPO 427s, noteably the factory ZL1-powered models (9560) with 430bhp (closer to 500 according to some) with a 0-60 time of 5.3 sec, and 1/4 mile in 13.16 sec @ 110 mph.
...Compare that to the 1969 Corvette ZL1 427 (430HP) which could do 1/4 mile in 12.1 seconds @ 116 mph... Sadly, only two were produced...
Toronado
But if GM puts the 5.3 L in the Z/28, it would cannabalize sales of the two unless GM reworked the 5.3 to put out 350-ish BHP. Besides, I'd like to prevent putting crappy, 40 year old Buick engines in a brand new car.
Its hard to say it would "cannabalize" the sales of the other models, as the Z/28 was always less-powerful and slightly de-tuned suspension wise as compared to the SS. There are many different versions of the 5300, going from 295HP up to 325HP in the top-line aluminum DOD V8 that will be available in the new GMT900 Tahoe and Yukon. Using what is a modern 327 sourced from trucks would guarantee good ammounts of horsepower, torque, dependability, and the adaption of the truck's 5-speed stick would also cut costs...
Then again (I never really thought about it), GM could use the 4.8L V8 out of the Silverado/Sierra which puts down 285HP and 295ft/lbs of torque. They are available with the 5-speed manual as well, and are actualy quite powerful in the worktrucks... Hell, GM could play with the bore/stroke and make a 302 if they wish, and could push the power output just north of 300.
...This must be the hardest part of designing a new vehicle... Deciding whats going under the hood...