Redline performasnce make the original Hemi six Holley manifold,use a 600 CFM,and you can bolt the 265 head straight on,same part!.What you really need is the E38 head with bigger valves.All performance bits are available over here for hemis,make a date to travel over to the annual Chrysler days at Mt Gravatt or South Australia ( Chryslers on the Murry) .
http://www.hemiperformance.com.au/
Just a note here,My Mum had a E38 Charger in NZ ,bought it new from Wright stevensons in TeKuiti,had it two weeks and traded it for a V6 Capri.The dealer picked up a couple of chicks took them out for a demo and wrote the car off...two weeks old!!