Are you sure you have a retired police car?
The last model Chevy Caprice police package came with 4L60E transmissions and LT1 motors. The instrument cluster had a vacuum flourescent digital speedometer, with analog tach, fuel, temp, and oil pressure.
In 2000, a friend of mine in Utah picked up a Utah Highway Patrol Chevy Caprice with the Police Package at a State auction:
- LT1 V8
- 4L60E motor
- 4 wheel disk brakes / ABS
- HD suspension
- 184,000 miles
The UHP ran the recommended Mobil 1, but they used Mobil 1 10W-30 instead of 5W-30. He picked up the car cheap and did the AutoRX treatment immediately.
The oil came out quite a bit darker after that, so he ran a few flushes with Dino and much shorter OCI. Motor is fine now, though he runs Mobil 1 15W-50 year round.
The trans was slipping already so he got a new one from Pace Performance, along with replacing the factory Limited Slip with a Powertrax No Slip. Drives like new.
He also got the Lingenfelter adjustable thermostat for the electric fans, so the cooling fans kick on at 185 instead of +210. For stop-n-go driving in Salt Lake City, that really helps.
With the LT1 he was able to put in a "T" fitting and run a mechanical Autometer oil pressure gauge. 25-35 psi hot idle in Drive, 65-75 psi hot at Interstate speeds.
LT1 motors hold up well with basic care, especially if you run a good synthetic. If the motor is worn though, you can call Pace Performance and get a crate motor LT1 for $4,146.
BTW: General Motors Performance Parts recommends at least a 10W-40 in ALL their crate motors, including LT1 and LS1 motors.
Hope this helps.
Jerry