Am wondering if a 4.8L will run using an ECM configured for 5.3L and if so, how well will it run. Basically, I bought an ECM configured for a 5.3L with VATS disabled thinking I had a 5.3L. But it turns out I think I have a 4.8L. I was going to start the engine on a stand just to test it and make sure all is good before stuffing it into my 53 Chevy. I'm currently working to get my bench harness working to program ECM myself, can read but having issues writing to ECM. So until I get that issue resolved, am hoping I can at least use the ECM that already has VATS disabled but is configured for 5.3L. Anyone have success doing this type of test?