CP: Thanks... but I am very green about this. I do not understand what you are saying because I am not familiar with the term "lock out" for a dist. This is what I know: I had to retard the timing a little for the street, I used a timing light (which worked fine) & I did this by moving the distributor back manually. I have a 6al, & separate MSD retard box w/ 4 chips (which I removed the box). So what I believe I have is the 6al, with a mech. hei & separtate coil (MSD)... no points distributor w/o vac advance. setting timing has only been done through a manual dist adjustment. It has 5.5 inches of vac @ idle, w/a Lunatti cam (solid) that is pretty healthy. What i did not know is if the vac advance would help low end/idle a little. It seems fine now, but NOW is all I know! I also don't really know where my timing should really be... so I started with a stock BBC timing of 12BTC & worked my way up to where it is now by listening & driving. Oringinally I think it was @ about 36. Thanks for the schoolin'!!