From another web site
From the Engine Assembly Code you posted, 1M0521 4VP; 1= Chevy, M = Mexico, 0521 = May 21 (assembly day), 4 = 1994, VP Engine Suffix Code = 350 CID, 260 HP.
From another web site
See if this helps...found this when looking up mine
If it is 10066036 then it's a GM goodwrench crate engine.
Here's ALL of the info on that engine.
350 Cubic inches 4.00" Bore, 3.47" stroke
8.5:1 compression ratio.
250 HP @4300 rpm
350 ft. lbs of torque @ 3600 rpm
( These Numbers obtained with a Quadrajet Carb,1 5/8" headers , and an Edelbrock Performer intake part # 2101)
Engine consists of the following parts:
Block -part # 10066034, casting # 10066036
2 piece rear main seal 4 bolt main
Crankshaft- # 3932444
Nodular Iron 1985 and older flywheel bolt pattern.
Powdered Metal Connecting rods- # 10108688
Cast Aluminum Pistons-#12514101
G.M. High Volume Pump Oil Pump- part # 12555284
Hydralic Flat tappet Camshaft- #14088839
Intake Lift-.383" Exhaust Lift-.401"
Intake Duration @ .050"- 194 Exhaust Duration @.050"- 202
Lobe Seperation-112
This cam Has a mechanical Fuel Pump Lobe.
This is a low end Torque oriented camshaft.
Cylinder Heads- part # 14034808, casting #33417369, 1.94" Intake valve, 1.50" Exhaust Valve, 76cc Combustion Chamber, 7 Bolt style Exhaust Flange Standard, 85' and prior intake manifold bolt pattern. Perimeter bolt style Valve Covers. This head is very similar to the old #882 castings from the 1970's
This engine includes Painted Valve Covers, oil pan and Timing Cover. This engine is drilled for both L.H. and R.H. dipsticks. Plugs Are included to plug the side not used.Two timing pointers are also included, a pointer for a 6" balancer and a pointer for an 8' balancer.Balancer with 2:00 timing mark must be used with this engine in order for mark to line up with the pointer.
For most stock applications with HEI ignition, Base ignition timing should be set to 10 before top dead center (with vacuum advance disconected) Total ignition timing should be around 36 @ 3000 rpm.
Spark plugs that should be used are AC Delco R45TS gapped at .045"
Oil filters used with this engine include PF25 , PF35 , PF1218 , or PF35L. The first oil filter is a 1/2 Quart type, the last three are the 1 quart type.
Generally 10W30 or 10W40 oil is used in this engine.