vortec timing issues

[vince72]

i need help getting the timing on my engine perfect can i get help

i have vortec heads xe268 cam, 650 dp holley, air gap manifold, hei
i need all the timing initial,total ex..
thanks

[shmoov69]

All engines are a little different, but on my vortec headed small block (pre turbos) it had a thumpy hyd cam and so on. The best that mine ran was with about 14* inital and about 32* fully advanced. That is a good starting point, then tune from there.

[CarlC]

I agree with Jimmy, with a few additions.

Add in an adjustable vacuum advance. Tune it so that the advance is fully deployed at 9-10 inHg, and is adding no timing at 3-4 inHg. Set the initial timing at 4*, have the vacuum advance attached to full manifold vacuum and set to add 12* (16* at idle.) Full advance at 32*. This will give you a cruise timing of 44*. Add in a few more vacuum advance degrees to fine-tune the cruise. This also works well since when you shut the engine off the vacuum will drop and the timing reduced to 4*.

Set the mechanical advance to start advancing around 1100 RPM and be in fully between 3000-3200 RPM.