Maxi fuses

I have a general question regarding fuses, Maxi fuses and fusible links. I have a 68 Firebird that I just wired the battery into the trunk and also wired in a Ford type solenoid into the trunk. I placed an 8 gauge wire from the Ford solenoid (+ battery side of the solenoid) that i am running to the firewall of the car to provide power to my from wiring harness. I placed a 50 amp MAXI Fuse......its a large blade type plastic fuse like the one in the link.

http://www.wiringproducts.com/contents/en-us/d342.html

Whats the difference between the Maxi fuses and the regular smaller plastic fuses (smaller ones Im talking about look just like the Maxi but smaller)? Is it just that the MAXIs can be built to go to a higher amp rating than the smaller type or is there something more special about the MAXIs design?

My other question is....is that I would potentially like to replace the original fusible links that are 40 years old in my car with something like the MAXI fuses. How do I determine what amp rating MAXI Fuse to use to replace a 12 gauge fusible link, a 14 gauge fusible link or a 16 gauge fusible link?

Does anyone have any quick tips on how to do it.......I read it has somthing to do with sizing the fuse or fusible link to blow at 80% of the wire's current capacity (80% of the wire the fuse is protecting). But I know that fusible links are more forgiving at blowing than a regular fuse is so I wonder if this also played into the selection?

A Maxi fuse is simply a lager version of a regular fuse. There is no way you could build a smaller fuse to 50mp rating.

For wire sizes and fuse rating there are general guidelines as follows.

14 awg wire 15 amp fuse
12 awg wire 20 amp fuse
10 awg wire 30 amp fuse

Sizing wire per a load is usually calculated by figuring 125% of max anticipated load. Sizing a fuse for 80% of wire capacity is sound engineering practice.

Vince