1. After installing the engine, ensure the crankcase has been filled with 20w50 racing motor oil (non-synthetic) to the recommended oil fill level on the dipstick. Also check and fill as required any other necessary fluids such as coolant, power steering fluid, etc.

2. The engine should be primed with oil prior to starting. Do this by using an engine oil priming tool. If you do not have one, one can be obtained through GM, part number 12368084. Follow the instructions enclosed with the tool. This is the sure way to get oil to the bearings before you start the engine for the first time. Also, prime the engine if it sits for extended periods of time. See short block instructions, GM part number 86962927, for further information.

3. Safety first. If the vehicle is on the ground, be sure the emergency brake is set, the wheels are chocked and the car cannot fall into gear. Verify everything is installed properly and nothing was missed.

4. Start the engine and adjust the initial timing. Set the ignition timing to 20° before top dead center (BTDC) and the engine idle to 950 RPM (ZZ572/620) or 1200 RPM (ZZ572/720R) with a timing light and the vacuum disconnected and plugged. Rotate the distributor counterclockwise to advance the timing. Rotate the distributor clockwise to retard the timing. Leave the vacuum advance disconnected.

5. When possible, you should always allow the engine to warm up prior to driving. It is a good practice to allow the oil sump and water temperature to reach 180°F before towing heavy loads or performing hard acceleration runs.

6. Once the engine is warm, set the total advance timing to 36°F at 4000 RPM.

7. The engine should be driven at varying loads and conditions for the first 30 miles or one hour without wide open throttle (WOT) or sustained high RPM accelerations.

8. Run five or six medium throttle (50%) accelerations to about 5000 RPM and 55MPH (if application is a vehicle), and back to idle (0% throttle) in gear.

9. Run two or three hard throttle (WOT 100%) accelerations to about 5000 RPM and 55 MPH (if application is a vehicle), and back to idle (0% throttle) in gear.

10. Change the oil and filter. Replace with 20w50 racing motor oil (not synthetic) and a PF35L AC Delco oil filter. Inspect the oil and the oil filter for any foreign particles to ensure that the engine is functioning properly.


11. Drive the next 500 miles under normal conditions or 12 to 15 engine hours. Do not run the engine at its maximum rated engine speed. Also, do not expose the engine to extended periods of high load.

12. Change the oil and filter. Again, inspect the oil and oil filter
for any foreign particles to ensure that the engine is functioning properly.

13. Do not use synthetic oil for break-in. It would only be suitable to use synthetic motor oil after the second recommended oil change and mileage accumulation.

ZZ572620 and ZZ572/720R Component Information Ignition System
The high energy ignition (HEI GM part number 8896l867, included with the ZZ572/620 is a self-contained ignition system that includes a magnetic pick up, a module, coil, rotor, and cap.

The HEIs large diameter cap minimizes arcing and cross-firing between adjacent spark plug terminals. The caps male terminals provide a reliable, positive connection for the spark plug leads. However, the HEIs large diameter cap may interfere with other under hood components in vehicles not originally equipped with HEI systems. Check for adequate clearance before installation. The HEI distributor incorporates a hardened (melanized) drive gear that is compatible with a cast iron cam gear. Use of a non-hardened distributor gear will result in excessive wear.

The HEI system requires a 12-volt power supply for proper operation. The HEI system should be connected directly to the battery with a 10 or 12 gauge wire through a high quality ignition switch. If you are installing an HEI in an early-model vehicle originally equipped with a point-type ignition, be sure to remove or bypass the resistor in the wiring harness to ensure the HEI receives 12-volts continuously.
Use distributor connector package, GM part number 12167658, which includes connectors and wires for the HEIs tachometer and 12-volt terminals.

The multiple spark discharge distributor, GM part number 10093387, included with the ZZ572/720R does not include a coil or ignition control module. Both must be purchased separately. This distributor requires the use of GMs heavy duty ignition control, GM part number 10037378, and heavy duty ignition coil, GM part number 10037380, to function properly. Follow the installation instructions included with the ignition control and coil components.

Timing Information For Both Engines
Set spark timing at 36° BTDC at 4000 RPM with the vacuum advance line to the distributor disconnected and plugged. This setting will produce 36° of total advance at wide open throttle. The HEI vacuum advance canister should remain disconnected.

Flexplate
The ZZ572/620 has an automatic flexplate included with the engine assembly, GM part number 12561217. If a manual transmission is to be used, a manual flywheel, GM part number 12555135, must be purchased separately.
The Z2572/720R does not include a flexplate with the engine assembly due to wide variety applications and event sanctioning body regulations. You must choose one that suits your requirements.

Important
Both engines are internally balanced and require internally (zero) balance mating components. Always tighten the fasteners in a star pattern to 30 ft.lbs. first then to final torque value.

Pilot Bearing
You must install a pilot bearing in the rear of the crankshaft if the engine will be used with a manual transmission. The pilot bearing aligns the transmission input shaft with the crankshaft centerline. A roller pilot bearing, GM part number 14061685, is recommended for this engine. The heavy duty bearing adds an extra margin of reliability to a high performance drive train.

Indicator Tube
The indicator and indicator tube come installed on the engine. One end is pushed into the hole on the oil pan and sealed with an o-ring. The other end is fastened to the block using a bolt and a spacer. When removing the dipstick to install the engine or headers, be sure not to loose the small o-ring which seals the dipstick tube to the pan. The o-ring must be reinstalled on the dipstick tube before inserting it into the pan. Make sure the tube is bottomed out in the pan before tightening the dipstick tube to the header bolt. Also, the spacer and fastener that were attaching the dipstick tube to the engine will not be required once the headers are installed. They were for shipping purposes only.

Carburetor
Please refer to the documentation supplied with the carburetor for installation and tuning instructions. If you have technical questions regarding the carburetor or cannot locate the instructions, please contact the carburetor manufacturer at (706) 864-8544. The air cleaner size should be at least 14.0 in diameter and 4.0 tall or with equivalent surface area to allow adequate air flow to the engine.

Exhaust Header Information
The engines were developed using 2.25 diameter x 36 long primary tube headers with 3.50 diameter collectors.