Call Brad at Stans Fibertech directly on the cowlings. The website listing is not right. Brad knows which one you need. No one else makes the cowl for the Palmer plans. The drawing shows a half cowl or belly pan type of setup for the nacelles. You build the top half of the cowl and nacelle and use the fiberglass part for the lower half. If my experience with the Bronco and Stan's stuff holds, they will fit very well.
I have not decided what to use for power. Palmer specs a MVVS .48 engine that can be rotated to exhuast to the rear (
http://mvvs.nl). Using an MVVS mini tuned pipe then you can exit the exhaust in the scale location. I don't think the .48s will handle the real weight of the C130 so I am looking at MVVS .61 with the same setup or RCV .61-SP 4 stroke (
http://www.rcvengines.com/rcv60sp.htm). The RCV will fit very well inside the cowl and will let you swing a scale size 4 blade prop. I need to look at sizing and cooling before making a decision. Electrics are still out there but the cost is way to high right now.
Palmer uses Robart Fowler flap hinges (
http://www.robart.com/Hinge.aspx) to actuate the flaps to simulate the fowler flaps. Looks like it will work but like most of Palmer's designs the devil is in the detail.