I have a race coming up. my head is ported and polished and ready to go. But i am running out of time to get a aftermarket ecu and tuning done.

Can i run it on oem ecu??

i know it would idle like a pig.. I dont care.

I'll idle at 2500 rpm if i have to.

as long as it makes a bit better power where it counts??

please help i want to know before i go doing something stupid.. like will it lean out and blow up?