I know this is an old thread, but I've been waiting to voice my opinion for a long time. My buddy just posted on Facebook a picture of his new "5.0" and it got me thinking about this again. The consensus here is that the Ford 302 is 4942 cc, and I have verified that thru Wiki and some Googling. In college, I took a physics lab and we learned about significant figures. Example: If you measured two dimensions, let's say as square 0.7 by 0.6 inches on a ruler that had 0.1 increments, the best you could say was that 0.7 dimension could be anywhere from 0.65 inches to 0.75 inches and the 0.6 dimension could be from 0.55 to 0.65 inches. So the area could be anywhere from 0.3575 to 0.4875 sq in. So, when you quote the area, you would say it was 0.4 sq in and you would qualify that with a +/-, but to say it was 0.42 sq in without qualifying a margin of error would imply that the area could be from 0.415 to 0.425, which would simply be inaccurate. And there would also be a calculation to give the margin of error, but I think we got the picture now, and my memory from the class many years ago isn't that good. But let's just say that we all agree that the engine is 4942 cc, and that is accurate, and the previous discussion would be applicable if you were calculating this figure from the bore and stroke dimensions. Since we didn't include a 10ths place in the cc figure, the engine could be from 4941.5 cc to 4942.5 cc. Converting from cc to liters, we move the decimal place and come up with 4.942 L. If we use our rules of rounding, and round to the 10ths place, we have a 4.9 L engine. If we round to the whole digit, we can say that we have a 5 L engine, but we can not extrapolate that we have a 5.0 L engine. We would at least have to have a 4.95 L displacement to label it as a 5.0 L, because we can round 4.95 up to 5.0, while we cannot round 4.94 up to 5.0.
In conclusion, if you use scientifically accurate measurements, the legendary Mustang 5.0 should be labeled as a Mustang 4.9. If you look at Wiki, they correctly quantify the size of the engine as a 4.9 L.
If you go the other way, and again, agree 4942 cc as fact, when you convert from metric to U.S., you get 301.579... cu in. Here you can round up to 302 cu in, the advertised U.S. volume of the engine.
Thanks for staying tuned in.