Personally I wonder if it's a 1982 HO that is being talked about, or a roller HO. What hasn't been mentioned here is that the roller HO cam will require roller valvetrain, and if I'm not mistaken, the camshaft itself won't work with your block. (Roller conversions are made for a different camshaft diameter, aren't they?)
The 1982HO cam is as follows:
.416/.445 198*/208*@.500 and 260*/274* overall.
I think the standard cam back then was the same as the 255
.380/.380 244*/244* overall.
The 1979 5.0's used
.381/.397 244*/256* overall
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