10w-40 synthetic blend will it work in replacement of 5w-20 in hemi 5.7 liter truck

I'm no oil or engine engineer, even tho I'd like to get paid to play one on TV...that said, you should stick with the original weight oil the engine was designed for. Only use a higher viscosity only if it's a last resort to keep the engine running. Use a good quality oil and filter and change it on the factory recommended schedule, whether u use conventional or synthetic oil. I prefer full synthetic. I have a '96 318 with 232K miles and have always used quality oil and filter. The engine STILL runs like a top and only consumes 1 quart every 3thousand miles.