Under 15k, the C4 Vette should be on your extremely short list. Anything 86-91 should be within reach, up to 93 might be depending on condition and location.
The L98 engine in the 86-91 Vette gets a bad (and undeserved) reputation for low HP - it has an extremely restrictive manifold design that produces great torque (350ft/lb+) but low max HP (~250HP). Engine can't really breathe above 4,500 RPM. At any rate, they're stupid fast for a toy. That, or about $1k in engine mods (Lingenfelter SuperRam and matching cam) will get you to ~350HP.
L98 has the added advantage of being a Perfectly Normal Chevy SBC. A normal, distributed engine without any technological trickery like OBD2 or Opti-Spark. It's parts-compatible with about half the planet.
Did I mention I love my 91 vert? Pic in sig.