Hi guyz! I've decided to broaden my horizons and jump over to this forum too. I have been a member of Team Chevelle for many years. I figured now I should learn a little about full size Chevys.
Welcome to the Team Frank!
I was interested to learn that a mid eighties (1977-'90 B-body is about the same size and weight as the 1970 Chevelle. Same four link rear suspension (though the rear coil spring is attached differently and it has different control arms) and the same style front end that uses a lot of 1968-'72 Chevelle parts or vice versa. I used a 12 bolt out of a 1970 Chevelle under my '85 Impala initially.
I was even able to use headers off of a 454 '70 Chevelle that bolted in place on my '85 Impala.
But I will wager you don't even consider those full perimeter framed years to be Impalas, instead you are probably looking to the vintage "X" frame 1958-'64 cars that are the most popular, or the 1965-'70 series that is nearly as popular.