what is required of a switch to the 5.3?

[opc patrick]

Ok… this may be a silly question but I am new to all this… Basically forcing myself to lean something new. I am working on a 1950 suburban. My goal was to build something I could cruse in with the family and still look cool and original-ish. When I bought it, it had a running and driving 350 in it from a junk yard. I purchased another frame and I am building it up with a mustang II and new TCI rear springs. I also have a blazer rear axle with disk brakes. So now I am questioning putting an 5.3 liter vortec and 4L60E transmission in it.

Question, if I go this route does that require me to get an aftermarket speedo? I am trying to figure out what all that engine change would require down the road besides just the pressurized fuel system.