why are fiero's so heavy?

[MrPbody]

One can speculate all day, as to the weight. The only sure way to find it is to drive the thing to a scale and WEIGH it!
Who ever said the 2.8 is very heavy, has not tried to lift one. I have an '86 GT, an '86 2M6 SE and have had two 2M4s. The fact is,. the 2.8 is quite light and very compact, both were primary design criteria. A 2.5 weighs about 100 lbs. more, dressed, than the 2.8. One 2.5 head weighs more than two 2.8 iron heads. You may not believe it, but that's okay. It's true. My '86 GT weighs 2,650. My '86 SE (6 cyl) weighs 2,550. My '85 2M4 weighed 2,710. I have no information on the weight of the '84.
This "curb weight" can be different from one car to another in the same line. It isn't unusual. Options, density of materials, etc. all contribute. You can use the published weight as a guideline, but not as fact. Only the scale knows for sure...
There are a few V8 kits out there. The NorthStar has become very popular. Hi-tech and all that. The president of the local Fiero club has one with the 3800SC. He's afraid of it (cool!). The nastiest one I've seen belongs to the Ferncliff Flash (Dave Windingland of Dave's Auto Parts, Ferncliff, VA). It has a Pontiac 455 in it, attached to a TH325 from an '81 Riv. It rides and drives like a stock Fiero, but runs low 11s on 87 octane fuel, and will go all week, with the 3.15:1 gears as final drive. If anybody cares, there's a pic of it on my shop's website (centralvirginiamachine.com). He calls it "Fear Arrow". It sure is purple! No hack job, though. This thing is right!
I'm very curious about the one spoken of above with the 350 Chev in it, that puts 700 horsepower to the ground. Could you elaborate as to what modifications and power adders are used to make this much power from a small block? It must be well over 900 at the flywheel, and that's a BUNCH!

[fierangero]

my smog certificate says test weight is 3000#

my ranger's curb weight is supposedly around 2800, but in reality it is 3100. so curb weight means diddly squat

[Black Lotus]

My '88 Formula 5 sp with air weighed 2,780 lbs on a truck scale with about 10 gallons gas.
I you consider that the chassis is not, and never was a "space frame" but more of a bastardized "backbone cum unibody" you'll understand why it isn't a super lightweight.
If Pontiac had ditched some of the plastic body panels and continued the chassis "proper" out to include welded on steel body panels (the outer metal skins being stressed panels--like other unibody cars), they probably could have taken a lot of meat out elsewhere, saving weight.
Other items like suspension components seem to be overbuilt as well, contributing to the weight. I mean CAST IRON for the rear suspension uprights, what's up with that?
The flip side of the dead-weight plastic body panels is-- they seem to be remarkably ding resistant.
BTW, the only reason you'll see a weight listed ON the car or in the owners manual is to tell you what the Gross Vehicle Weight is-- the GVW. That's the max weight the car can carry safely. It has little to do with the curb weight.

[MrPbody]

Like every other data item on the net, published information is a no more than a guideline. To know how much your car weighs, you need a scale.

The 2.8 weighs about 30 lbs. less than the 2.5. The block is a toy. Actually, the little 60 degree V6 is an excellent power plant for its mass. While you can't extract high power numbers without pumping it to the teeth, you CAN get decent torque and a very fun driver. Stroke it to 3.1, add a cam and some head work, and they run quite nicely. Of course, if competition is your goal, they're limited. The bigger 6s or a V8 are more suited to racing.

At the time of production, Fiero was the only American car EVER built to Swedish (most stringent in the world) safety standards. The little P-body is a tank!