I ran a set of stock 87 302 castings on a mild 79 360. Simply because I had them and the stock 79 heads tore out an exhaust stud that had already been repaired.

In an 87 Diplomat I lost about 15-20 mph top end (115 vs estimated 130'ish on the cop speedo)compared to the stock 79 heads and a set of J heads I tossed on it later. However, I gained lot's of low end torque and with an Edelbrock 1406 carb I would get low - mid 20's for mpg.

I would not use them for anything hotter than a mild 360 myself and only if I had a set lying about. If I had to buy a set of heads I would start with Magnums at the least.

They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.