360 trouble. please help

I took my 360 punched it out 0.040 and used kb 107 with rebuilt iron heads with 2.02 1.60 valves ported and polished. My crank is a scat 4" stroke and stock rodsI used a comp thumpr cam 279/296 with a Holley strip dominator high rise intake with a 660 street avenger carb I bought a Chevy style HEI distributor off eBay actually all parts were off eBay, everything shipped was around 2500$ CAD and the machining was 400$. I dyno this combo 458 hp at 5400rpm and 489 ft lbs torque at 3800 rpm great combo with he right fuel compression and timing