Yes the lumina 3.4 DOHC has a timimg belt and a chain. Do you know what you are talking about? I do.

 

I believe there is some confusion here. The 3.4 MPFI does not have a timing belt. However, the 3.4 Twin Cam engine does have both.

A little confusing because they both have the same displacement.

Those twin cam timing belts are a bitch to do, I had two of them.

 

Yea i am fixing too have too do the timing belt on my 3.4 i have not done one of this type. Any thing you can tell me that may help? I am looking over my G.M. shop manuals but i am not seeing what to do whenever some one spends the teeth off the belt and it dose not brake. So yes anything that will help me.

 

A timing chain lasts longer and is more reliable imo, a timing belt has to be changed, lined up, adjusted, etc. total pain.

See I never had a 3.4 Twin cam engine, only the standard 60 degree v6 3.4L MPFI.
That engine was a total boss!
Now I only got the 3.1L v6, I am thinking of making it a 3.4 ish by changing the cam and adding some boost. It already was modified to rev up to 7,000 RPM, idk how or why, but it was and it does, and it has been for years, and its still running perfectly fine.

Its in a Beretta INDY. Centrifugal supercharger FTW!