Hey Ginko, Steve here, I have a 93 LT1 Corvette w/ SOHC, The car has 118,000 mi. on it..Problem started about 4 weeks ago when I added coolant and bled the coolant system of air..Long story short, I killed the Opti-Spark..Diag code 16..Replaced complete Distributor,,Still no Spark..Replaced coil..Replaced Ignition Module..Still no start.Replaced ICM with old ICM and finally car started, but ran rough..then stalled..checked codes again. Now it's throwing a Code 41 which is Spark Timing..Im going crazy..any thoughts..Thanks in advance..

Have ODBII codes read and post here.

Could be thermostat,check coolant level,air filter,fuel filter.

Block and Basics
Displacement: 350 cubic inches, 5733 cubic centimeters, 5.7 liters
Block Material: Cast Iron
Main Bearings: 2-Bolt Centers and Ends (The Corvette LT1/LT4 had 4-bolt mains)
Stroke: 3.48"
Bore: 4.00"
Compression Ratio: 10.4:1
Combustion Chambers: 54 cubic centimeters
Factory Redline Rating: 5700 Rotations Per Minute

Bottom End
Piston Material: (10159437) Eutectic Aluminum/Silicon Alloy
Connecting Rod Material: (10108688) Powdered Metal
Crankshaft Material: (12556307) Cast Iron

Top End and Valvetrain
Cylinder Heads: (10168448) Cast Aluminum, 2 valves per cylinder/16 valves total, ~212 CFM flow (Impala SS and Caprice heads were made of cast iron*)
Valve Diameter: (intake- 10241743, exhaust- 12550909) 1.94 intake, 1.50 exhaust
Valve Overlap: 41*
Valvesprings: (10206040) 85 lbs, seated
Camshaft Specs (12551705): 205/207 duration @ 50*, .447/.459" lift, 117 Lobe Seperation Angle
Rocker Arms: (10089648) 1.5:1 Stamped Steel
Timing Chain: (10128485) Powdered metal link

Intake and Fuel Delivery
Fuel Delivery: Electronic Fuel Injection, sequential port
Injector Size: (17124248) 3.0gps, 22lbs/hr speed density (1992-1993), 24lbs/hr mass airflow (1994-1997)
Throttle Body: 48 millimeter twin butterfly
Intake Manifold: (12552137) Aluminum

Factory Power Ratings
92-96 LT1 Corvette: 300bhp, 330lb-ft
1996 LT4 Corvette: 330bhp, 340lb-ft
1992 LT5 Corvette: 375bhp, 370lb-ft
93-95 LT5 Corvette: 405bhp, 385lb-ft
93-95 LT1 F-Body: 275bhp, 325lb-ft
96-97 LT1 F-Body: 285bhp, 325lb-ft
96-97 WS6/SS: 305bhp, 335lb-ft
93-97 Firehawks: 315bhp, 340lb-ft

Factory LTX Camshaft Specifications**:
1992 Y-body: 205/207 0.451/0.450 lift 117 LSA
1993-1995 Y-body, F-body: 202/207 0.450/0.460 lift 116 LSA
1994-1996 B-bodies (including L99 4.3L): 191/196 0.418/0.430 lift 111 LSA
1996 Y-body, 1996-1997 F-body: 200/207 0.447/0.459 lift 117 LSA
1996 Y-body, F-body LT4: 203/210 0.476/0.479 lift 115 LSA


hope this helps

on the lt1 it is above oil filter

Start by checking the Timing of the valves.

Dennis I have a 93 z/28 lt1 car and I find most issues are coil, icm, or optispark....O and i want to give u poines for my jaguar solution but dont know how also check out this lt1 forum...I am louvit on there....http://ltxtech.com/forums/forum.php

yeah. This is only a temp fix. GM has a bulletin warning against the use of Slick 50 w/PFT. It can clog oil passages

Has the Optispark distributor cap been replaced yet, if not have it replaced.

from the service manual.
Connecting rod nuts, tighten evenly to 20 ft pounds then turn another 55 degrees of rotation, seems odd but i have the factory manual

Check to see if your water pump is leaking coolant from the weep hole. If it is, it may be causing to Opti Spark distributor to cut out.