[Mr70]

I have a 1970 Chevrolet engines Dyno test catalog.
I know we'd all like to think Chevrolet was conservative with the Horse Power ratings,but
in it shows the graph charts and Gross Horse power specs for all the 1970 engines.
It shows the LS-6 tested at 448 peak HP.Other engines from that year were around what they were advertised or less on their respective Air Cleaner labels.
These were engines with Exhaust manifolds as delivered into the car.