Using Simon H's approach but a "Flex-A-Lite" universal fan/shroud You might have and easier fit. Although the Flex has less FPM the shroud seems to make it work. It is a bit thinner than a SPAL.
The Morgan Spares unit is a "Flex-A-Lite" plastic fan blade cut down. On My +4 I have it cut down but more radical than the MS Unit as well as a custom made sheet metal shroud. I also try to stay out of 100 degree weather.
On a +4 TR engine the tuning is very critical regarding heat generating. The timing must be spot on and the carbs set properly. This IMO is more Art than Science.
