Friend has a 383 that he is wanting to do a startup on. His obd2 ecm still has his tune from when it was a 350 my question is will it run really lean because of the difference or can he get by with it until he sends the ecm out?

 

He can certainly start it. but I would advise against putting it under much load.

Rich

 

Thanks

 

If ya went with larger injectors than what the tune is for it will be way rich and maybe wash down the cyl's and cause the rings/cyl walls to slick out and not seat.
If this is the case I WOULD NOT run it but a few seconds if at all.