Willow

I inherited a 674 IH diesel. It has had a lot of what looks like "temporary fixes". I am slowly rebuilding this tractor but also having to use it at same time. It apparently doesn't have glow plugs and I am having a very hard time getting it to start up in anything colder then 45-50 degrees. It does have a magnetic block heater on it all the time now when it's parked. My question is, would adding a second block heater help start up? Can I use an immersion heater with this tractor and would that be a better option? Thank you in advance for any help and patience as I learn