when cranking a motor over for the fist time with the DFI 5, what should I set the base timing to? I was think 6º but I wanted to get some opinions.

 

The Accel DFI manual suggests zeroing in the entire timing matrix to 6* for Chevy's as a starting point. You can use any numeric value you wish, a higher value can help keep the engine alive. Then sync your timing at the crank to correspond with the timing shown in the box below the timing matrix.
If you've already uploaded a timing map for your DFI, start the engine and just advance or retard the distributor till the timing on crank matches number the box below the timing matrix.
How much timing an engine like varies from engine to engine, even two identical engines. Start at 6* and work from there. Hope I didn't make it sound confusing. Its morning and I haven't slept yet. LOL. Hope this helps.