Gene, thank you for chiming in. This is the type of info I am seeking. I have been driving a 361-2bbl 1967 D600 loaded way past the GVWR and so far so good. With all of that weight I can stand on the gas and the engine won't rev quickly. It might be different with a 440 and 4-barrel. We did get it started up on the 4150G and drove it around the yard a bit. Runs good, revs quick!