Thread: tuning and timing questions???

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Originally Posted by C9x

Did you note Skids72 comment about setting the timing with the vacuum advance disconnected?

If you don't you'll end up with retarded timing.

With the cam you have and assuming the timing is retarded 11" vacuum is about right.

If . . . the engine is idling at 600 rpm or so and you increase rpm to about 1500 the vacuum gauge will indicate 17"-19" of vacuum.

I'm asuming your vacuum gauge is connected to full time manifold vacuum.
If it's connected to ported vacuum you'll get readings that are not correct.

yes, i did all timing with the advanced disconnected. and that is good to know that the 11" of vaccum is alright, less to worry about then.

well thank you all for your help, finally got the purple people eater running good!!

Originally Posted by tim_bo16

yes, i did all timing with the advanced disconnected. and that is good to know that the 11" of vaccum is alright, less to worry about then.

well thank you all for your help, finally got the purple people eater running good!!

Keep in mind that if you don't pick up to 17"-19" vacuum at 1500-2000 rpm with no load on the engine things still aren't correct.
If it does, then everything is probably ok and you just need to pursue the timing the engine wants.

If you can't get the vacuum above 15"-16" you may have the cam a tooth off.