[v8volvo]

Excellent info.

Don't forget that if it is an early D24 head you may need to have machine work done to it in order for it to be compatible with your later bottom end. The headbolt holes will likely need to be reamed out to the later 12mm size.

Before getting too far into this, though, you may want to do more diagnostics on the motor to be sure it is a headgasket. Try getting an infrared thermometer and testing all around the engine. Your gauge may be wrong, or your thermostat may be malfunctioning. Aim the thermometer at the thermostat housing to be sure it is running at the correct temp the t-stat is rated for. If the temp at the lower rad hose outlet (at the thermostat housing) is significantly lower than the temps in the bypass circuit (test at the outlet from the t-stat housing that faces towards the rear of the car, going towards the heater hoses/fuel filter area), then suspect a bad thermostat. Those hoses coming from the side of the t-stat housing should run at about 190F/90C if the t-stat is working right.

If all temps on the engine look normal, then your gauge may be faulty. Not an uncommon thing on 240s.

A good infrared thermometer is a great tool to have, a good investment and a lot cheaper and easier than tearing into a HG job that might not be necessary. Do the diagnostic homework before you plunge into the big job -- you will be glad you did.

How is your heater output?