Originally Posted by Read T

This is the best video i can find for seafoam
instructions for seafoam (break booster) - YouTube

I have yet to do it on a 370 but it should be the same concept. There should be a large vaccum line running into your brake booster. Disconnect the line from the brake booster while your car is running. Your engine speed should drop and the car will try to die unless you hold your finger over the hole in the vaccum line. As a friend keeps the gas pedal slightly depressed (so the car won't die) remove your finger from the end of the vaccum line and either pour seafoam into the brake line or stick the end of the vaccum line into a container containing the seafoam. Apply enough accelerator to keep the car from dying. After about 1/3 of the can of seafoam is sucked up, reconnect the vaccum line and continue to let the car idle until no smoke is seen out of the back. There will be copious amounts of thick white smoke behind the car.

I take no responsibility if somehow this messes up your car. Even though it's a petroleum product I'm not sure if it is possible to hydrolock an engine or damage some weird engine this way. I use seafoam all the time on my 240 and morgan.