I bought a 91 z vert a few months back and now I'm ready to start playing with it.... its a orig 305 TPI (Lb9) and a M5, it now has a 350 swapped in (still has the stock 305 heads) and it has headers on it... how can I tell if it was a 205 or 230 hp car origionally?
BTW its white with a grey interor, and it was in boxes when I bought it... but all the special vert pices were there... so I bought it, its almost ready to go now...

 

According to what I've heard, look to see if your car has a G92 option ... I think all of them were 230 horses and all that weren't were 205 horses. I might be wrong on this ... somebody correct me if I am.

 

i want to say for sure it was the G92 option, which is an upgraded rear end...and according to my resto packet that GM sent me, the 230hp LB9's had 3.42 gears with a 5spd, as opposed to 3.08 gears and a 5spd for the 205hp LB9. so i'm just putting 1 and 1 together. if this is true, then you're convertible does not have the G92 option, because it was only available in Z28 coupes. hope this helps

 

90-92 Z28 convertibles were not availble with G92 package (230hp option) All were base 305tpi/205hp cars with 2 1/4" single cat exhaust, manifolds, and a 2.73 or 3.08 rear, for autos and sticks respectively.


G92 package consisted of performance positraction and special rear axle ratio, rear disc brakes, dual cat exhaust w/ 2 3/4 I-pipe and larger manifolds - thats about it

 

thanks, that clears it up then, so with a z28 and a M5 the only rear ratio I could have would be 3.08 then? I can live with that...