I ran a single pattern
[email protected] 110 lsa 106 icl solid in a 400 and idle was right at about 850-900 rpm.... About 10" vacuum in gear with an 8" convertor. With your longer stroke I'd expect your cam to behave at least as nice.
Power... The dual plane intake is probably going to hold peak power down some... I'm thinking @575 hp 600 ft lbs.
Personally I'd try a T2 or Victor or at least the equivalent of a well ported HSD.