Steveo has a good point about the injectors at idle with too much fuel pressure, if you're too rich you might wash your bores down with fuel.

I accidentally started my new L31 engine with it's last best stock TBI engine tune and it idled okay, it wouldn't of had enough acceleration enrichment to make it move but it ran. I still had 15.5 PSI of fuel pressure though.

My stock TBI engine with headers was running out at 4000 RPM with the stock fuel pressure.

The requirements for the Vortec/TBI combo with the stock cam aren't huge but it can use more timing than the stock TBI timing tables have.