Ephry,
Your not tryin' to start a flameout again are you?
Just ask yourself, If someone can add boost pressure and the extra heat that goes with it, thru turbocharging, using 103/4 and/or 5's then why can't I use them normally aspirated?
Wally yes you are correct the barrels do go square (Russ had that happen on the first incarnation of his latest setup)
He ran the piston barrel clearance a bit too tight and the mixture was a bit lean.
He has had the pistons and intakes ceramic coated to insulate the parts from excessive heat.
Funny you mention nickies cos an option we're still considering is the stock 100mm 993 pistons with dome top and whopping compression,so we can use the 100mm nikasil barrels from Porsche.