Quote:
Originally Posted by ron10
to me,1970 was the last year GM made a true Z28 worthy of the badges.
|
I can understand your point but the advertised power numbers alone varied much due to the following reasons. The car itself didn't.<caveat, crazy rear axle ratio's did go away beyond '71, foggy memory, I gotta follow up on that if you want> 11:1 Compression dropped after 1970 to 9:1 from '71 through '74 by 2 CR. That's at best 10-15 less per point. Solid lifter cam and aluminum intake with 780 Holley 1n 1970-1972 versus cast iron intake, hydraulic HP cam and Quadrajet from '73-'74 was probably a net loss of af about 15-20 HP. So, a drop in 50 HP from the height in '70 versus '73-'74. Not a ton. Advertised BHP in '71-'72 was 330 due to the compression drop of 2 CR. Most importantly don't forget advertised HP rating after 1970 changed from BHP to Net in 1973. Chevy HP was listed at 245 Net for '73-'74. If the motor was rated under BHP as previously before instead of Net, it was more likely to be 310 HP. Big difference in ratings. More actual than the previously disclosed value's before the HP ratings changed. I drove them all. '69 Z included, which was probably 360-370 HP but listed by Chevy at 290 BHP. They all had swag.
