I agree with silver 1,build your own engine that way you know what parts are in it. I have heard some horror stories that I wont go in to too many details but parts charged for not in the engine, cheap parts instead. I am building my 383 tpi stroker myself and it has not cost a fortune to build a bottom end that will take 800+ hp. Check out summit racing online, I got most of my stuff there except the crankshaft because shipping and exchange rates were too high on that. Only paid $900 for the crank here and its forged 4340 5.7 inch stroke for late mod block.Cast is much cheaper but not as strong,depends how fast your wallet is. I am aming at 600+ hp so I went forged. I have a program for the pc that helps predict what power you will get,it says its within 3%.Its crane cams desktop dyno if you want to run a couple of combinations send me your specs and I will run them for you and give you the results, it gives you a full graph. I have done a few for mates and it has been close.You need everything but even cam specs and carby cfm, head type, valve size,rod length,comp ratio and header type and exhaust. Its a lot to put in esp. the cam specs but it gives the best results when you do. Takes a bit of the guess work out of it.