1995 Z28 LT1 backfires

I ran into a guy selling a '95 with a new LT1 (about 5k on the new engine) but when I took a test drive, it backfired at high RPM: I took it on the service drive and lit it up. It took off nice but when I
backed off the gas pedal, it backfired. Any ideas what it could be?
My first thought would be valve springs or a bent pushrod, but it's a new engine and would hope they are still good. Maybe it's opti-spark or the plug wires arcing?
Any thoughts would be appreciated. DM
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Could be the knock module, stock lt1 knock modules are bad. swap with lt4 knock module. i'm not sure what u mean by backfiring though... it could just be bad gas, too, try some injector cleaner and refill tank with good premium gas --william
On Mon, 16 May 2005 06:17:17 -0700, gprimerib wrote:

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