small block with msd 6 and new blaster 2 coil and mallory megnetic pickup diz,i wont get spark sometimes when hot,like today i only ran in the garage to set timing and idle it was not drivin so i didnt think the electronics would get to hot but it didnt get spark for 15/20 min after cool down,i replaced coil,plugs,cap and rotor,could it be the old diz,i was thinking of a getting the 85551 msd diz with vac,has anyone run into this problem with msd 6 or mallory diz,the msd 6 is about 3yrs old

You need to isolate where your loosing spark when hot.If you dont have your msd instruction sheet, you can find the test procedure at msd website.Test your box , if it works then move to the coil, then dist.