Just to put this in further perspective: I'm building my A15 now, after machine work, custom pistons etc. the bottom end is at $2200.00 when I add my existing GX head, FCR carbs (which I got cheap) header I'll be $3000 and again I got some smoking deals on some of these parts. Also I put my labor in this...........whats your time worth, even at $10 an hour your gonna have $400-500 in labor?? My motor will likely be 20HP down on this one. $4500 for a professional built complete A15 is a good price. Sure you can do a conversion (for 7-10K) but for some of us, race rules make sticking with an A series the way to go..............again this is a well priced deal.