One thing to look at, you probably already have, is the water jackets in all the parts...
Boats generally cool the engine by flowing the water they are on through it.
This makes for a very quickly wearing engine, from the water jackets out.
If it was ever in salt water, the problem will be even worse.
Marine engines don't use antifreeze or any anticorrosion in the cooling system like cars.
Your engine can look great outside, and even inside the pan, but can be paper thin from the water jackets being abused.
Enough of that...
With the right cam, you will like this engine in your car.
It has the same balance and uses the same external mounting parts as your 302, so it will be a direct bolt in.
Use your 302's flexplate, bellhousing, dampner (if needed), pulleys, engine mounts, etc...
Depending on the oil pan, you might need to track down a front sump pan from a 351/400 in a car application.
In a 67 you will actually have plenty of room for this engine. Swaps don't get tight until 65/66.
Check my info, but I believe that 70 351C headers crossover to 67-69 swaps. 99.85% sure.
Bolt it in and let us know!
Good luck
Dave