I can’t Answer about the 2 gen because I have never owned one. But I think the 1 gens are lighter. I know In 91 they did redid the radiator core support, there is more room to run a mechanical fan. I am not sure but I think on the 87 to 89 or 90 if you put a V8 in one, you had to use a electric cooling fan. No room for a stock fan. My friend races a 87 with a gen 3 Hemi