[dirty joe]

ok guys, what spark plugs you guys recommend for my combo-455 .060 over, 670's milled .060, flow 284/245 @ .550 lift, solid f/t cam, 4500 victor intake. has about 13.5 compression. i want a recommendation for n/a. but then, when its tuned, im goin to spray 200 or so. and i recommendation for the spray. also, what gaps on those plugs for both n/a and the spray? thanks, joe

[smagnotti]

First off you better atleast have the drivers side of the motor chained down when you hit the spray!
I would go 2 heat ranges down from the stock plug, which I belive was a Delco R44s, so r42s would be the one to run with the spray.
Each plug number has a 600 degree heat range to work properly in, so if you plan on producing twice the horsepower as a stock motor you need to go down at least one heat range.
As far as the plug gap goes, you made no mention of your ignition set up, but a HEI with a good aftermarket coil can do .060", if not above 6000RPM with stock stuff,.045" with a load of spray is better.