I dont know who you are dealing with. I just got a block back from SFP. They use ERL and install Darton sleeves. It took 2 weeks. The cost was $1399 plus $70 for shipping. Chavez sells GE for $980. Thats why i told you to go with them. When i give advice i have nothing to gain. I'm just going off of my own mistakes and experiences that i have had or made. You do what you want but i'm makeing ober 500whp and plan on making 700+ when i'm done with my GE block. As far as Darton not having GSR's you are right. Thats why SFP buys them off of me for 1000-1200 dollars. Because thats what they are worth. Good GSR's are getting rarer by the day. I have sold all but one of my GSR blocks. I think if i need another block i will by one straight from Darton.