Vintage drag race question

Is anyone here old enough to remember what D/Modified Production cars ran in the mid 1960's? Did they run flat tappet or roller cams in M/P back then? Found this pic in an old book and though it would be cool to build a tribute engine. Just wondering what the performance potential might be. I have a 273 core but might use a 318 just b/c it's easier (cheaper) to get a set of forged 318 pistons. Not really interested in making it a 360 or a stroker.

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