the 300ci 6cyl was a great engine. sorry. i actually had one in my bronco... couldnt kill it, but again it was a dawg!
Well it was a truck engine, so very low hp, with very high torque. I had a 300cid in my F100 and it was a great engine. With a little work to the head and a cam, intake/exhaust, it was pretty strong. ~350-400hp which is pretty good for a 300cid engine with minimal money put in to it. A lot of drag racers use the 300, there is an aftermarket crossflow head for it. There's a guy that runs something like 9's with a NA 300cid engine in his altered. There are also a lot of guys that turbo them and run similar times in street legal cars. I am selling all the parts i had, and just sold the intake to a guy in ohio with a 300cid that is NA and runs low 10's.
But from the factory, yeah, they are slow. But they are a terrific truck engine, strong, reliable, cheap, and good on gas.