I just did that exact swap and NO the gas c-6 case will not bolt up to the adapter on the diesel engine. I went the other way and had to put the guts from my diesel c-6 into a gas case as the diesel c-6 will not bolt up to a 460. The diesel does have a vacuum modulator and a kickdown rod. The ratios are the same. The internal changes are in the governer assembly and a different converter.