[rwest]

First blush is that there should be an hose going from the top of the engine to the heat exchangers near the muffler. It would have also been routed to a blower fan and from that fan to the heat exchangers. Search blower delete and you should find more info.

I’m not sure if having that just blowing air into the engine compartment would steal air from cooling the cylinders or not. For the time being you could try duct taping something like a spray can cap over it to see if that helps.