I had a few issues with ARP also, I did catch them before I got the engine assembled though.
First was I bought the stud kit they make for the Edy heads and the studs that go on the inside of the head were too short, about 3/16" I called them and they told me the length they are suppose to be, I also called Edy and when I checked them it was correct. I finally realized they had too much thread on the lower portion of the stud so they were going into the block farther than they were designed to.
Second was their washers do collapse each time you torque them, I found this out when I was checking the clearance in the lower end. When I asked them, they said that was normal. Hmm???
Third was their stainless dress up kit, I had to place a new special order just to get the correct bolts for the 70 and up timing cover and water pump, the intake bolts were to long for the corners of the intake, so were the ones that hold the coil, and the valve cover bolts don't fit aluminum valve covers.
Some of this may sound petty but I feel a company that claims to be the professionals should do their homework a little better. I talked to a guy at Edy about the head bolts and he said I wasn't the first to catch that which made me wonder how many guys don't have their Edy heads torqued down correctly because they don't know you are suppose to have a minimum of 4-5 threads above the nut when they are torqued down.
I bought my bolts 5-6 years ago so some of the issues I had may have been corrected since then. The head gasket blowing could be because of the washers, They are the same ones they use for the main bolts/studs.