When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I don't know that the HD 300 was ever put in an F150 from the factory. They were in some F600s. At any rate, there are few if any reports of cast crank failures. The HD crank is good for a warm and fuzzy feeling but really no more than that.
There are some all metal gear sets to which one can swap but they install the same way. So far as I know timing gears working loose isn't something common with 300s. The phenolic gear failing seems to happen to a lot of folks eventually, though.