dieselpower

Hey all. So my older brother has a 84 gmc 2500 sierra classic single cab long bed with a 4inch lift running on 35inch bfg mud terrain and im probly gonna get a 83 chevy scottsdale k20 single cab longbed and want to put the same lift size and same size tires but ive herd people say you have to have a 6inch lift to clear 35s. Does it vary between these two almost identicle trucks? There almost same year. Same size. Same package. Same engine. (Detroit 6.2) so i dont know why it wouldnt work the same. Thanks for your time.