Compression ratio help...

[Andy(UK)]

Hi,

Im looking for some help on a topic Ive never really got to grips with. Compression ratio.

Im trying to decide what CR to aim for given the grades of fuel available in the UK, 95 & 98 RON unleaded. Im building up a 1971 Ford 302 hopefully at stock or the lowest overbore possible. Ive got Higher performance stock size crank and rods, the cam is still up for discussion (cue another posting) but probably a comp cams High Energy 268H or the XE268H. Ive got a new set of Edelbrock rpm heads (2.02” intake set) performer rpm intake and I will get either a 500 or 600cfm Edelbrock carb to sit on top.

So what compression ratio would I be best aiming for given UK fuel grades and to make the best out of my engine bits?

I don’t think I want to use forged pistons as everywhere I look says don’t use them on the street (various websites, and my Des Hammil book).

So if anyone has any words of wisdom or experience they can offer I would greatly appreciate it.

Cheers

Andy