I''m building a 351w stroked to 438ci. Dart block 9.5 deck 4.125 bore, Eagle crank 4" stroke,Eagle H beam rods 6.2" and JE Dome top pistons with 14.5 to 1. I was looking at the AFR 225 heads Part # 1456. Anyone have advice. Please dont reply if you dont know not being rude. This will be a all out race engine w/ two stages of nitrous.  

That's out of my normal zone, but that never slowed me down...LOL

438 is a lot of CID and with a big bore, the cylinder can really pull hard on the intake.  The valves will not have the cylinder wall so close and the intake port will likely work better than it might normally.  A 225 cc intake just seems a bit small for that application - my 351C-4V has a 220cc intake port.  Obviously you'll need good exhaust flow with a two stage on it.  You might want to look at these items - First Jon Kasse Small Block Ford Heads They are a canted valve design.  Info link at Jegs is HERE but I can't find the parts on Jeg's site.  Might have to contact Kasse for particulars.  Maybe Jeg's isn't the dealer right now.  

Also look at the CHI 3V heads - they are ostensibly for a Cleveland but they will do either.  CHI 3V 260CNC  They sell a matching intake also.  The CHI heads are the ones that regularly kick butt at the PHR Engine Masters.  Excellent heads - if my budget allowed I'd have a set of their 4V 228s.