That does seem to have a bit of a relaxed profile...
I snagged some of the links I have saved that pertain to the mighty 305. These might be interesting. the crankshaft coalition one mentions a couple times that the 305 doesn't have a fuel mileage advantage over a 350. That is a surprise to me. I want to see if I can find the EPA estimates for our trucks back then. Your LG9 is different than an LE9, but does have good torque numbers which is the number that really counts in my book. The 416s are good heads to have. The other two links are 305 engine builds.
https://www.crankshaftcoalition.com/...evy_305_engine
https://www.motortrend.com/how-to/cc...Cx87PGLphGsT5c
https://www.firebirdnation.com/threa...-owners.15985/