You're doing nothing but leaving torque and power on the table, messing with the 273. For what you'll spend on the 273 reciprocating assembly you could easily buy a 360 stroker crank and pistons and build a 408. Better yet do it to a late model magnum engine. You'll end up with a 400-450 HP engine instead of a (maybe) 300 HP engine. You can then just tell people it's a 273 :D