Never heard of 10 vane pump. 6 and 8 are the common ones on a mopar small block. And I had the same issue on my 78 fury 318. Original was 8 vane went to 6 vane and it ran hotter. As soon as I replaced the water pump.
I had had the radiator boiled out 3-4 times while trying to figure out what was going on. I bought a 3 row champion radiator and a flow kooler water pump. Now it runs almost too cool.
I think that it would have started running hot soon even if I hadn't had to replace the water pump. If everything is marginal it don't take much to make it run hot.
