Have 5.7 LS1 with 750 Prosystems Holley, 236/242 600/610 Comp Cam, Daytona Sensor SmartSpark LS. It ran good on start up but had a little stumble when revved. Then had a big backfire that popped the power valve. After that it has no fire in #1 coil & on & off in #6. Sent box back to Daytona and they say it’s ok but large cam may be problem. Could crank sensor be problem? Any ideas appreciated first time with LS.

Checked the plugs all good gaps even switched 1 & 3 coils same problem no fire on#1

Checked grounds, power, battery is good don’t really know how to test thruDaytona harness which has GM connectors. Waiting for Tech to return my call.