Still stuck on the heads. I spoke with Jegs, they started substituting promax import heads for their 514080 vortec heads recently without changing the description online. I got one better head and the other is from promax. The castings are the same, even the same casting number, but the machine work is not exactly the same. I think the castings were always imported, just one supplier cared a little more about parts and machine work. Anyway I think I solved the retainer to guide issue with a new set of springs and retainers. A 20lb increase in spring pressure is not a bad thing anyway. Then I found the spring seat needed cut for the inner spring. Summit sent that cutter by Ontrac, what a joke. They have no local office, you can't call the driver. If your not home they keep the package and try the next day. I have been trying to get the tool for three days, but the van shows up at different times and I have a full time job. Eventually I will get heads on the engine. I did do most of the 409 exhaust last weekend.