145? Wow, never knew that in 26 years. Lol. 300 Hp was some simple bolt on parts.
You must know the 82 was the lightest at 3078 pounds, or did Wickepedia not tell you that?
Front suspention was re-designed for comfort as most third gen owners complained of harsh ride. More G's in a third.
Much of is doors and fenders?
Way cheaper to build a cast iron block for the same or more power. But then, I live in a word where small blocks are like. Elbows.
May be cheap in the US but after shipping, import tax and VAT, the cheapness in the UK evaporates and buying a crate engine might well be cheaper. IROC-Zone quotes the 82 Z28 at 3169lbs, 135lbs lighter than a 4th gen or 270lbs, depending on where you get the weight, manual vs auto, options etc.
My 87 Z28 was pretty much base spec Z28 with no leather, manual windows, T5 manual and not even a heated rear window so not much came lighter but the stock 175hp LG4 was not a great engine and the guy i sold it to slotted in another V8 with Corvette heads and a lumpy cam.
The plastic on a 4th gen was front wings and door skins and hatch but the inner frame was all steel. Of course a lot of the 3rd gen was plastic too. Much of the weight penalty must also be put down to bigger wheels and tyres (I think 165/xx 15 on my Z28 and something like 235/xx 16 on the 4th?)and more gears in the gearboxes, LSD in the diff etc.
Just so we're not at odds, the 4th gens over here are as cheap as the 3rd gen these days and you know g's aren't the be all and end all of a good handling car. So what I'm saying is the argument is immaterial when you can buy a good LT1 4th gen for around £3000.
I do confess my LS1 had Bilstein suspension and springs, SFCs, STB and BMR LCAs though.