I am looking at a new cam and lifter kit for the beast as its got a noisey lifter thats driving me crazy! I dont know much about cams, yet.
Looking for a lumpy idle and strong mid-high range power.

I only want to do it once. below is a list of engine mods so far;

World Products Windsor Junior Heads
60cc combustion chambers
180cc intake runners
64cc exhaust runners (from memory)
Mild port to clean out casting floors and gasket match ports
Mild polish chambers to smooth off casting roughness
ARP rocker studs and head bolts
Scorpoin Roller Rockers 1.72 ratio
Crower hardened cromolly pushrods
Comp Cams Valve springs
Comp Cams Timing Chain set
Home Made Underdrive crank pulley
Standard short block, including camshaft
Ported Explorer (AU or EL185KW) intake manifold with 1/2” phonelic spacer
AU 65mm Throttle Body that has been epoxy filled and blended
Granatelli 75mm MAF sensor with standard Ford electrics
K&N air filter and breather filters
Dual Innovate Motorsport LC1 wide band oxygen sensors
32 channel data logger with tune on the fly hardware.
1 3/4” Ceramic Coated Difillipo 4 in to 1 extractors with 3” outlets
Steel core high flow cats
Standard XR8 replacement Excedy Clutch
Nolathane uppper and lower diff control arms
3.75 LSD
5 speed manual gearbox
Diff centre rebuilt approx 2 years ago by Western Manual Gearbox and Diff
Cross drilled and slotted front, and slotted rear brake rotors
XR6 Drivers seat covered with original EF fairmont seat cover
this is my daily drive so its got to be drive-able.
cheers!!

TFS1, Crane 2030 /2031
Fords F303
I personally wouldn't too much go over 220 @ 50 and tighter than 112 lobe centre
on a 5.0 D/D..
Better breathing heads can take more lift or more the point they keep flowing at higher lift..
Check with your head flow charts ...As a guide...

I'd go the F303 too but, I'd throw those heads away...they're rubbish.

would gt40 heads flow better? I am hoping to work with what i got.

Depends which GT40 heads and where in the lift range?
If you look at average flow over stock you can see part of the reason they don't stack up...
Obviously flow figures aren't the whole story either. It's the quality of flow and other things like chamber design that makes the difference. Quite simply they're an old design that doesn't perform.
You could get them improved by porting but you need to know that whoever is doing the work knows what they're doing otherwise you've blown your dough that could have been used on a better choice out of the box.