I'm looking at buying a Gen V block to use in place of my mark IV. I can get a good deal on it and it has most of the machine work done on it but I am not familiar with all the differences between the two blocks(or the Gen VI). I do know about the one piece rear main and the adapter I need to run my crank. Will my 4.25 stroke crank clear without any work or do I have to clearance the block? Also the lack of the fuel pump boss on Gen V. Any helpful info would be greatly appreciated. I need a set of blower pistons and rods too, .060, 4.25 stroke, 6.385 rod.