I have been having a problem with the rotors comming loose on my 525SC's. I have bought brand new ones and locktite them on. this works for a couple weeks and they are loose again. I was thinking about MSD dist, with the rotor that screws down. anyone have any Ideas?

I have msd distributors in my 525's no problem with them.

I have MSD's and hav'nt had one problem with'em for the 4 yrs that I ve been runnin them.
If you go that route, stick with the billet ones that have the adjustable collar. They sell them in 2 styles, 1 with the weights locked in, and 1 that has the weights loose for the centrifical advance. Buy the ones that are locked in, especially on a S/C combination. It'll give you full total advance at idle, which will give you better off throttle response, a crispier idle, and better docking abilities. I think those are the ones that are a little bit more money, but just by a few dollars.

Lock your timing in at 28-30 degrees at idle and forget about it. And even with 30 degrees total at idle, you won't have any problems with cranking at startup.
We've seen too many problems with the advance type distributors breaking springs, not having the advance come in when you need it, they're just not worth the extra problems.