Well carnut...I stand corrected. Seems in my old age..ahem,ahem..I was giving the old LT4 more credit for acceleration than it could actually muster. (All those crazy small block folks musta taken over my mind and made me believe it to be true...just kidding my GM friends)
This is fine by me as I am a Ford guy and hey....the slower a Vette is the easier it is for me to beat him. With the LT4's barely mid 13 second performance stock that means even a new Mach 1 could take one out...I am all for that.
As for the ZR-1....if my failing memory doesn't bring up any doubts...... lol.....I seem to remember 1/4 mile times for that car being wildly unpredictable from one source to the other over the years in both hp ratings they came in. (Latter version was just a tick over 400, don't recall exactly what earlier cars put down) Moreso than you might find for the vast majority of cars.
At times, this made me wonder if maybe Mercury Marine wasn't getting very liberal in how they screwed those things together. I even think Motor Trend once said something about how one ZR1 would just scream and the next one you got your hands on was nowhere near as stout.
There is some variance in production, but it is usually small unless Q.C. is lacking somewhere. Just a thought.