For the oil pan; The Chinese Conspiracy is real and active. I built my 400sbc with Fel-Pro gaskets; the front cover-to-pan seal started dripping after about 500 miles and after 15k was throwing out a quart every 2000 miles. I thought surely I'd done something wrong, or used the 'thin' seal instead of 'thick'. After searching a bunch of sbc forums I found that it was a common complaint recently, and that it seems the seal is made of cheap Chineseum that hardens quickly and shrinks. So my advice is this; no matter the brand, give the pan seals a reasonable coat of Ultra Gray or Super Black RTV when you install them.