500ci rb msd timing help/advice

Find what it likes best for total locked out. Figure out if you want any curve in it, Back it off 10 degrees and see how it idles.

I have bushings for MSD distributors that limit advance to 10 and 14 degrees. I doubt you'd need a 14. IQ hit it, probably going to want at least high 20's for initial. If it starts OK locked out, why bother with any curve using a cam that large.