Pyrometer First.
Then you can try and turn up the fuel. A N/A IDI can and will make dangerously high exhaust gas temps, especially when worked hard. Turning up the IP will only make it get hotter, quicker. You can melt it down if you don't have a pyro to know when to back off.
Pyrometer First.
ZIGGSTER'S PAGE has all the info you need to do it.
By the way...........get a pyrometer first.
Heath