1968 Shelby GT500

Setting the timing

Look closely inside the distributor, inside the cap base, you will see the number 1 molded into the cap and into the base. These obviously indicate the number one piston in the compression cycle. In the second picture you can see how I recommend marking the distributor base. First I highlight the “1,” then after I get the engine timing set perfect at 10° I mark that position with a short fat line that lines up with both edges of the rotor. Then I remove the distributor and mark a longer skinny line that shows where the rotor should be pointed before the distributor is dropped into the block. All these marks may seem like overkill, but it is my web site and these are the best ways to do the job. You’ll thank me later when it saves time on distributor work if the need arises in the future.

Before you install the distributor make sure the engine is at TDC for cylinder one, and you have mounted the TFI to the side of the distributor. Drop the distributor so the rotor is aligned with that 1 molded into the cap. Note that the actually positioning of the distributor to the block is not important; we are aligning the rotor inside the distributor with that 1. Make sure there is enough room to rotate the distributor in the block 1/8th turn. You will need to rotate it to set the base timing of 10° before TDC


1. Insure the key is OFF position
2. Place transmission in PARK or NEUTRAL, A/C and heater in OFF position.
3. Connect timing light.
4. Disconnect the single wire in-line SPOUT connector or remove the shorting bar from the double wire SPOUT connector. Examples of the SPOUT connector:
SPOUT connector on our EFI harness:

SPOUT connector on Remote TFI vehicles may be on the inner fender:

5. Start the engine. To set timing correctly a remote starter should not be used. Use the ignition key only to start the vehicle. Attaching a remote starter might disable or initiate the start mode timing after the vehicle is started.
6. Read the timing from the engine dampener on the crank.

7. If the timing does not read 10° before TDC continue to step 8, if timing matches 10° before TDC skip to step 10.
8. Shut engine OFF, and loosen distributor enough so you can twist it with your hand. Do not loosen it to the point where the engine rotation moves the distributor.
9. Re-start engine and twist distributor to a point where 10 can be read aligned with the timing pointer.
10. Shut engine OFF, reconnect SPOUT connector, and insure the distributor hold down bolt is tight.
11. Re-start engine.
12. Check timing advance to verify distributor is advancing beyond the initial setting. (This confirms Computer control)
13. Shut off engine and remove test instruments.

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