Heater Box Question??

I think you would have heat, but maybe too much. Hardly an expert, but I think the way the heating temperature adjusting lever work is that it mixes in outside air to cool the mixture delivered. The "hot water valve" under the hood is just on-off (think), so heat or no heat, depending on your switch. At least this is the way I think it works in the A-bodies I had (1965 to 1969).

Actually good that Mopar didn't use a proportional hot-water valve to adjust temperature. That is used in my 80's Mercedes', and it works really poorly (for everyone). I read that climate system was one Mopar dropped in the early 60's and M-B bought the rights.