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built a motor about six months ago and have been adding to it as cash allows. i have gotten in to bracket racing and been running in the mid 13's. my rod is an 85 IROC. modifications are : 305 bored .060 over, 305HO flat top pistons, speed pro 468/480 lift 304/287 duration cam, 305HO heads milled .2000 's (i believe) ported with 1.94 valves, edelbrock tunnel ram, holley 600 CFM VS, MSD standalone distributor, long tube headers. after building the motor i found that the harmonic balancer mark wasn't true anymore. so i have been doing my best to set my timing by ear and feel. lately since i put the custom heads on i'm having a hard time getting it timed correctly. my question is what is the best method to setup intial timing without having any reference except #1 at TDC. if i can ever get a fairly accurate initial setting i can have a better chance at setting up a decent timing curve on my distributor. Thanks in advance. Sick
 

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First I would check to make sure where TDC is and make a mark on your balancer.......Use an engine stop in the #1 hole...hand crank it one way, make a mark and rotate it the other way and make a mark. 1/2 way between the marks is TDC. Then at least you know what your initial timing is.
 

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Thanks for the reply but, now i'm confused. i thought TDC ( Top Dead Center ) was when the #1 piston was at the very top of the compression stroke? from what your tellin me that isn't so. if i'm reading your right TDC would be at the bottom of the stroke? Sick
poncho62 said:
First I would check to make sure where TDC is and make a mark on your balancer.......Use an engine stop in the #1 hole...hand crank it one way, make a mark and rotate it the other way and make a mark. 1/2 way between the marks is TDC. Then at least you know what your initial timing is.
 

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You are right...it is at the top......That is why you go in both directions against the stop, and then measure in between the marks................

Another way to do it is with a dial indicater to determine when it is at the exact top.
 

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ok now i got ya. do you think on a racing engine that its easier to set the timing curve with or without vacuum advance? would it be simpler just to disconnect it and rely on centrifical advance? Sick
poncho62 said:
You are right...it is at the top......That is why you go in both directions against the stop, and then measure in between the marks................

Another way to do it is with a dial indicater to determine when it is at the exact top.
 

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SickSickSick said:
ok now i got ya. do you think on a racing engine that its easier to set the timing curve with or without vacuum advance? would it be simpler just to disconnect it and rely on centrifical advance? Sick
The timing is ALWAYS set with the vacuum advance hose dis-connected and plugged.

After the timing has been set, you can hook the vacuum advance hose back up.

For street use, I prefer to use a full manifold vacuum source. Some prefer to use the ported vacuum source.

For racing purpose the vacuum advance does not need to be hooked up as there is '0' vacuum at WOT and therefore the vacuum advance will not function regardless of where it is hooked up.
 
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