440 Source Head Opinions?

While there are far better heads out there I'm pretty happy with my stealths. On a budget I paid 1000 CDN for the pair second hand had them worked over pretty well ( new valves, guides were very tight so those were fixed as well a good bit of porting new springs to match and 10° locks and retainers for another 1000 at today's exchange rate that's 1600 US all in.
They made 642 hp at 5800rpm and 645 ft/lbs on my 400/500 engine. Could I have spent another 1000 to make a few more hp yes of course but on a budget I will say so far I am quite happy with these junk heads!!