Pics needed. Speedmaster intake.

Please provide more of your plan details. Are you running the entire Magnum accessory drive with alternator, power, steering and air conditioning? Are you running no air conditioning? Are you running manual steering?
The Speedmaster intake is basically the same as the other Chinese made air gap clones, in that it has dual intake bolt pattern for Magnum heads, but they use an LA thermostat position and bypass hose. The only real problem with those are the Magnum air conditioning bracket interfering with the thermostat location. If not running air conditioning, there should be no real problem.
Read through this thread for some other Magnum serpentine setups:
Confused what to do with a 5.9L serpentine setup