Vortec swap, timing question

[turner-zj]

My son and I have just finished putting a 97 vortec in his 95 z71. We used a 4 bbl intake with a TBI adapter. After driving it around for the first time it feels sluggish and will sometimes backfire thru the tbi. I timed it just like a normal 95 with a tbi, by unhooking the advance wire and setting it at what I believe is 0 degrees. The vortec has no timing tab but does have a little groove on the plastic timing cover. Did I do this right? Can you install a timing tab on the front cover? Help is much appreciated!

 

[IOWNJUNK]

Tbi can run up to about 8 degrees without any problems. Without a timing mark its gonna be hard to tell where that is exactly. You could keep advancing till it idles bad and back off it a little and try that. If you advance too far its gonna be a pain to start, especially hot.

 

[turner-zj]

The vortec front cover has a spot on it that appears to be a timing mark but with no numbers seeing how the computer controled the timing on the vortec. In my case I asume that mark is 0 and have set the tbi distrubtor at 0 off that mark. I was going to see if I could bolt a timing tab on the vortec cover and go from there. Also I've heard that using a tbi off a 454 motor is a plus as well on the vortec swap.

 

[skylark]

The vortec mark is for TDC. Just use an advance timing light where if you want 10 degrees, you set the light at 10 and dial the distributor until the TDC mark and the ballancer line up. Just to double check, you have disconnected the EST connector when setting the timing, correct?

 

[turner-zj]

I'm being told 6-10 BTDC is what I want to time it to. Any thoughts on what it should be set at?

 

[IOWNJUNK]

Its supposed to be 4 degrees before tdc. You can go more, but anything over 8 degrees and you'll get hard start problems. This is assuming everything is stock, if you can go 10 deg then run it.

Edit: Is timing advancing when you add throttle? If not then it will feel sluggish at best.