The stealth heads I got were really nice castings.
The springs and retainers are good for a decent sized hydraulic cam, but may need to be changed if using a large cam. The only item to note with the heads, is to use a large bore head gasket.
Their timming chain sets are nice too.

My machine shop re-ballanced one of their stroker kits, but I did not get the details why they did it?
I will pay closer attention to ballancing issues on the other kit I have.

I did get a timing chain oil slinger, and the crank hole was too small to fit over the crank snout. Their windage trays are designed to clear a 4.5" stroker crank, so they are too large (deep) to fit inside a stock style oil pan.
The aluminum rear oil seal retainer was slightly shorter than my oil pan rails, not a problem and maybe the same height as the stock seal retainer? I did not check the height of the stock one for comparison?
The ARP oil pump bolt kit for the HV oil pump are too long and bottom out before clamping the oil pump to the block. I few minutes with the grinder fixed that problem.
440 source customer service was good, and I would buy from them again. Those new cast valve covers look nice