You should have no problem. I run a 10A fuse on the little red wire (ign on 12V) and a 20A on my 7AL2. MSD specs 1A per 1000 RPM in the instructions for the 6AL2 and 7 series boxes.

From the MSD tech reference:

For example, an MSD 6 or 7 series ignition consumes approximately one amp per thousand rpm, so at 5,000
rpm the MSD alone is using five amps. An MSD is designed to produce full power sparks with a supply voltage of
10 volts, but if the supply drops below that, ignition output will suffer.