The absolute 'MINIMUM' cylinder wall thickness....

[SAJ]

Schwalms supplied a "touring motor" via Snyder's to me bored to 0.125 over. It has done 30000 miles since. Runs usually at 145. Deg F even though a 160 deg thermostat is fitted. Stat. starts to open exactly at 160 in a lab test. It is a vintage Precision housing and stat. It replaced a Snyder's stat in the upper radiator hose which also sat on 145 deg using the same temperature sensor. So I suspected the guage reading but an IR gun and a mercury thermometer in the radiator all read 145.
My wife's Tudor also runs too cool. It is 80 thou over and has a 160 stat in the upper hose.
No extra holes drilled in either stat for better flow when shut. No engine pans on either car and Roadster has an aluminium 2 blade fan and the Tudor a 6 blade from, I think, Bill Stipe. Both radiators run tap water and a green anticorrosive from Repco.
I thought Jim Brierly mentioned an even bigger bore than 125 thou on race engines.
SAJ in NZ