I have a 1990 k1500 4x4 with a 350 and a three speed trans with a low gear and to try and reduce the rpm's at highway speeds I wanted to put a 5 speed in it . Hears the question , did chevy make a 5 speed that will fit without any mods , at least not big ones ? Any help will be appreciated

there are alot of 5 speed 4x4 90's chevy trucks, very common, find an NV4500 tranny, started in 1988 in trucks, is truck 5 speed, aluminum case