I'm prepping my 600 f2 engine block ready to be painted. Do I need to primer it before applying some VHT black???

Thanks in advance.

 

Primer would help, but the most important step is cleaning it to the point that you could eat off it. The tiniest oil smudge or dirt on there will cause paint flaking and chipping. If the block has recently been bathed, I wouldn't bother with primer unless you're a perfectionist.