I think that it's awesome more manufacturers are producing aluminum Gen3 Hemi blocks!

Would there be major differences with your block vs. the Gen3 H3MI blocks available from High Horse Performance?

-Aluminum Water H3MI Block - $5,495
-Compatible with all Gen III 6.1L H3MI engine parts 
-Blocks are Manufactured from 357 Aluminum 
-Weight Approx. 110 LBS
-4.050 Bore 
-Lifter bores can be opened to 1.060" for a bushed-style lifter 
-Can be Machined for Large Keyway Lifter and 60 mm Cam Tunnel 
-Camshaft bearing support area increased to permit a 60mm roller bearing 
-Billet steel main caps with 4-bolt center caps strengthen the bottom end for severe applications 
-Crankcase clearance for 4.125" stroke crank (4.250" will fit with machining around oil drainbacks) 
-ARP Main Studs
http://www.gen3blocks.com
http://www.highhorseperformance.com/Gen3_Performance_Aluminum_HEMI_Bare_Water_Block_p/g3ppawb.htm