The voice here reminds me of detective noir pulp, which I don't mind. The problem I see is your tendency toward run-on, overly complicated sentences. For example:
The 327 v8 of my 69 Camaro RS rumbled down the streets of Washington DC parting the thick columns of steam billowing from sewer grates at 3:00 AM on a late November night and came to a stop in front of a building constructed on a grand scale with huge white columns and white stone that would have looked more appropriate in ancient Greece than in a modern American city.
First problem, it's confusing; from what's written, the V8 is what parts the columns of steam and comes to a stop before the building. Second, this is one long run-on sentence completely devoid of any punctuation besides the period at the end. It would be clearer broken it up into two sentences:
My '69 Camaro RS rumbled down the streets of Washington, DC, at 3:00 AM, parting the thick columns of steam billowing from sewer grates. We came to a stop in front of a building constructed on a grand scale: huge white columns and white stone that would have looked more appropriate in ancient Greece than in a modern American city.
Why those changes? The bit about the V8 engine was excessive detail that distracts the reader. The time bit was moved for clarity (i.e., 3:00 AM is when he drove through DC, not when the sewer grates are scheduled to release steam). Additional punctuation was also added for clarity.
One thing I didn't get when reading your samples, though, is emotional engagement. The writing is breezy and detached--emotionally distant. Now, I don't expect your character to wear his heart on his sleeve, but even Harry Dresden gulps or has his instincts "screaming at [him] to run." The second sample, which you say is near the end, should have rising tension; it's supposed to be building up to an ominous event. He should be fearful of what's at stake, which would remind the reader of why they should care about your character and fear his failure and death. This is missing. You're not engaging your reader. The writing is still breezy: nothing to see here; move along.
Also, you provide conflicting signals: "if I somehow managed to live through the night which at the moment seemed
fairly unlikely" and "the equipment I would need for a night of breaking, entering, snooping, and,
if it couldn't be avoided, violence." So in the previous paragraph, he expects to die, yet later on, he hints that violence could be avoided. Unless he's set to commit nonviolent suicide, the text is in direct contradiction of itself.