You sonic check 400's for wall thickness and mag it before you spend serious money on them.To find 400's these days is getting harder and then to find a good core is even harder.The oval track racers ate a bunch of them up.Then when you find a good core,you bore and finish hone with the machine shop having the pistons in hand using torque plates.

In terms of the Vega,what is your plan for the frame,suspension,and drive train??.