his model blazer never came in a 5spd, so it will all custom. The 4.3 you do have is basicly a 5.7 with 2 cyl cut off so you should be able to use the LT1 6speed tranny and clutch setup from a 93-97 F-body. clutch lines will have to be custom, you should be able to use the 95-04 4cyl s10 clutch pedal assm. for your truck.