I had one on my 5.2...wound up giving it to my brother for his 340. I had problems with coolant leaking into the oil, thought it was the intake sealing...I think the head gaskets were more at fault, but I'd heard the issues about poorly machined mating surfaces, so I just bought the Edelbrock intake and swapped the head gaskets--no more leaks. We put the crosswind intake on my brother's 340 and it didn't show any leaks until after we shut it down from the break in...no coolant in the oil, thankfully, but it did have a minor seepage coming from the front left corner.
I would buy another one if I needed one...and just mock it up before bolting it down, but that rule exists regardless of what you buy--always test fit first.