I had a 1963 C10 that came stock with the 283 SBC. Clearance was no issue.
As Lugnutz stated, engine mounts are the same. I currently have a 1962 that I installed a 327 SBC in after removing a 1967 250 I6.
I have a 283 awaiting some parts. I will convert the draft tube to a PCV system, so I’ll use aftermarket rocker covers.
No need to replace the valve covers. Here's how I converted mine to use a PCV using the Road Draft tube hole. You should already have the breather tube at the front of the intake manifold, so you should be good there.
Next, get a freeze plug that will fit in the road draft tube hole at the back of the block. Next, cut a hole in it to match a regular PCV grommet that would go into a valve cover, Install the grommet in the freeze plug. Test fit the PCV valve in the grommet. Make sure it slides in easily. You might have to adjust the size of the hole in the freeze plug if it's too tight. Once it's mounted in the block, it's difficult to change things. Once you know that the fit is good, you can mount the freeze plug in the block with the grommet installed.
Once you have installed the freeze plug, you can install the PCV and run the lines to the intake. I used hard lines, but rubber hose will work just fine.
Make sure you get the correct PCV that is sized for a V8. I originally used one for the I6 I took out. That was a mistake. Not enough draw and I was getting back pressure that was blowing oil spray out the breather.
I've included a few photos to illustrate what I did. I hope that helps.
