What are the symptoms/signs of this?

@@johnnytenjobs I noticed a big difference in performance when run a quart or even a quart and a half low. It was very noticeable and I had a reference route I took a lot to compare. My engine ran better cold so it wasn't the reduced cooling. There may have been a comment from one of the few project builders working with this engine. Information was where you find it back then, the speed shops laughed at me when I went in to ask about parts for a 4 cyl. Making friends with a Ford parts counter guy was my best source. Here in the US, a high performance 4 cylinder was considered an oxymoron.

​@johnelectric933 I see. Have you come across a book by David Vizard? There has been quite a lot of effort put into improving these in UK. Remodelling inlet ports. Extending the block height with a spacer and liners to allow a longer rod. Some clever stuff with split Webers or Dellortos for specific regulations have achieved impressive results too.

yes i do, ive even talked to Dave Walker about it, ultimatley its was pointless, it needed less ignition adavance than single plug, but gave exactly the same power

@@PenguinMotors was an interesting concept, great magazine too. Love your videos they are very educational so thanks for posting them Graham

www.burtonpower.com/forged-piston-93mm-cosw-38mm-comp-height-sc302-93.html

trailing side, but there are some rods out there that are factory notched both sides

How deep do you made the grooves? Planning doing same thing to my Volvo pushrod-engine H-rods.

It would be tricky to get right as you would need to mirror combination chamber shape. But either way it’s irrelevant now using a new head and a thin head gasket

No point in doing on a standard piston rod assembly

@@PenguinMotors thanks Graham.