Fan motor doesn’t fit behind the big block valve covers

If you arent a stickler for keeping the car factory, you could pull the stock heater box, and install a hot rod heater.
Speedway Universal Fit Street Rod Heater, 12 Volt, 20,000 BTU{match_type}&utm_source=bing&utm_medium=cpc&utm_campaign=SMI%20-%20Shopping%20(CSE)%20(Bing)&utm_term=4577679224227357&utm_content=Google%20Sucess%20Skus%20II%20(Feb28_2020)