I'm running 11.2:1. Static compression doesn't mean squat. Dynamic compression determines if you will have knock or not.

 

Exactly, dynamic compression is the biggest factor of knock/octane needed, I'm building a 12.1:1 377 for my chevy mud truck that has a dcr of 8.2:1 that should easily run on 93

 

Damn robots!

From what I recall, Ford replaced the complete pass side head.. Under warranty and after IF you biatched enough and new the correct number to call lol.. That was way back when tho. I haven't heard of a fix.

 

Exactly. My dynamic compression ratio is around 10.6:1. Definitely on the limit of running pump gas.

 

Rule of thumb in the chevy world is 8-8.5:1 dcr and a max of around 220 cranking cylinder pressure on 93 octane, it is a little harder building engines using carbs and hei ignition, can't pull timing or fuel like fuel injection without the engine running like a turd. Oh I remember the early days of nitrous and distributors, glad they're gone.

 

That's for heavy trucks, cars can have dcrs much higher

 

So how do you find your dcr? And what exactly makes that lower than the static cr

 

This is a dowel pin thing, isn't it?

 

If you Google it there are lots of calculators out there. I have a few bookmarked.

 

Awesome thank you